A method and apparatus for demodulation and correction of the broadcast signal of the digital audio signal that is compatible with the amplitude - modulated signal

 

The invention relates to radio broadcasting and can be used for demodulation and signal correction in the receiver that is designed to work in the system broadcast a digital signal that is compatible with the amplitude-modulated signal. The method consists in including in that the second set of correction coefficients, forming a second correction vector used for complementary bearing, determined by interpolation of the coefficients of the first population of correction coefficients. The invention also covers the operation of radios, which use the above method, device, operating under the above described method, and radios, which use the above-described correction method. The technical result - the loss prevention information necessary for the proper correction of the complementary carriers. 4 C. and 24 C.p. f-crystals, 5 Il.

The technical FIELD TO WHICH the INVENTION RELATES the Present invention relates to radio broadcasting and, in particular, to methods and devices for demodulation and signal correction in the receiver, designed for use in the system of the digital broadcasting signal EN is m coding, to achieve a higher quality reproduction of the transmitted signal is of high interest. In this direction proposed several approaches. One such approach, described in U.S. patent 5588022 (WO 95/24781A), provides a way synchronous broadcasting analog and digital signals on a standard channel, AM broadcast. The broadcast signal contains amplitude-modulated RF signal having the first frequency spectrum. Amplitude-modulated radio frequency signal includes the first carrier, the modulated analog signal program. The signal also contains a set of signals carrying subjected to digital modulation in the frequency band that encompasses the first frequency spectrum. Each of the signals carrying pending digital modulation modulate digital signal program. The signals carrying the first group subject to digital modulation, placed in the first frequency spectrum, modulate the quadrature relative to the first carrier signal. The signals carrying the second and third groups, subject to digital modulation, outside of the first frequency spectrum, modulate both in phase and in quadrature with respect to the first carrier signal.

THE 8022 (WO 95/24781A), a summary of the waveform to achieve the optimal data transfer rate through a digital signal and at the same time to avoid cross-interference with the analog AM signal. For the transmission of information through numerous supporting the method of multiplexing orthogonal frequency division (MOCR).

Mono detectors household AM radios only respond to the envelope, but not on the phase of the received signal. Using digital modulation numerous bearing eliminates the need for a means of reducing the distortion envelope arising from the transfer of a group of signal. In U.S. patent 5859876 disclosed a method of reducing distortion of the envelope in the system broadcast digital audio signal that is compatible with the AM signal. Certain carrying a digital signal whose frequency above the carrier frequency of the analog AM signal, correspond to the bearing of the digital signal with frequency below the carrier frequency of the analog AM signal with the same frequency shift. Data and method of modulating their upper carrier digital signal and corresponding to the bottom of the carrier are such that the addition of bearing does not give the components, in-phase with the carrier of the analog AM not located directly in the spectrum of the analog signal, called complementarity and modulated in phase and in quadrature relative to the carrier of the AM signal. This configuration provides substantial improvement in the quality of playback in analog AM receiver digital broadcast signals.

On the receiver digital signal demodulated through fast Fourier transform (FFT). One possible method and a corresponding device are described in U.S. patent 5633896 (WO 97/08877A). This patent disclosed a method of demodulation, in which the channels of the digital audio signal that is compatible with the AM-signal (ACV AM), and for the modulation format for multiplexing orthogonal frequency division (MOCR), thanks to the use of dual processes fast Fourier transform to split the respective in-phase and quadrature components of a received digital signal format MOCR unwanted crosstalk between analog signal and digital signals are minimized. To recover the data transmitted through the complementary bearing, use the output signal of the quadrature channel, and for recovering data transmitted through complementary bearing, use the sum of the signals received at Aty signal with multiple carriers need to adjust. Without such a correction detection signal would lead to significant distortions that impede the recovery information of the digital broadcast signal. Corrector increases the possibility of data recovery digital audio broadcasting. One such corrector disclosed in U.S. patent 5559830 (WO 96/23374A). Disclosed in this patent corrector includes a tool receiving waveform broadcast digital audio signal that is compatible with the AM signal, and the preservation of this form of the signal as a vector waveform. Then the checker processes the waveform by multiplying the vector form of the signal adjustment vector. This correction vector is formed by a set of correction coefficients, each of which initially assigns the specified value. Then the corrector compares each position of the processed vector waveform with the stored vector waveform. Corrector selects the signal quality is the position vector that is closest to the saved vector waveform. Preferably concealer contains the update tool of correction coefficients, which, using the vector form of the processed signal vector waveform and the stored vector forstalling in the patent 5633896 (WO 97/08877 a) and in the patent 5559830 (WO 96/23374 A) in the offset information is coming in the frequency domain in the form of a vector of the frequency domain. Each block of frequency domain information is stored as a data array. This vector data array is multiplied by a set of correction coefficients. The resulting work is a corrected signal. Since the corrector know a lot of exact values, you can compare each orientation vector of the adjusted signal. As the actual value signal choose the ideal value nearest to a given orientation of the vector. Vector solutions remain in the array of solutions. Using the received signal, the adjusted signal and the array of solutions, the evaluation unit calculates correction coefficients estimated values of the coefficients. To provide protection from noise estimated values of correction coefficients can be averaged over time. Update frequency coefficients determines the security of the offset from the noise and the degree of convergence. The coefficients on different parts of the range can be updated with varying frequency depending on the information about the mechanism of distortion.

Although the dual FFT allows to improve the performance of the system on the channel, which in the frequency range of complementary bearing is simme is different in amplitude or neenteeimmicy phase, the information contained in the signals, unbalanced amplitude or neenteeimmicy phase, in the process, where to get the data transferred through the complementary bearing, use only the output signals of the FFT quadrature channel is destroyed, which leads to the formation of incorrect control signal corrector. In the publication WO 00/21228 revealed the correction method, capable of providing a correct adjustment factors in the case, when the correction coefficients can be asymmetric module or participtation phase.

For demodulation complementary bearing may require the use of high-pass filter in relation to the in-phase component of the signal to eliminate penetration of the spectral components of the analog signal when performing the FFT. However, in the case of applying the high pass filter is the destruction of information in-phase signal that prevents the proper correction complementary bearing a digital signal. For channels that are in the spectral region of the analog signal there is no symmetry in the amplitude or symmetry phase, the destruction of information prevents the proper correction complemental environment on the signal propagation but also the fact that any component of the transmitter or receiver affects the amplitude and phase of the received signal. The present invention provides a method of demodulating a digital signal, devoid of drawbacks associated with the penetration of spectral components of the analog signal in the region complementary bearing, and destruction of information necessary for the proper correction of the complementary carriers. The present invention is to create an improved method of demodulation and correction and receivers that operate in this way.

Summary of the INVENTION the Present invention provides a method of demodulation and correction of the digital broadcast signal that is compatible with the AM signal. The method consists in the estimation of correction coefficients for complementary bearing and at the same time allows you to enjoy the benefits of combining information of the output signals from FFT complementary bearing. The method involves the use of information transmitted through complementary bearing, for evaluation by interpolation of correction coefficients for the complementary carriers.

The way demodulation and correction according to modulirovannym signal, containing amplitude-modulated RF signal having the first carrier, the modulated analog signal of the program in the first frequency spectrum, a set of signals carrying subjected to digital modulation posted in the frequency band covering the first frequency spectrum, and the first group of signals carrying subjected to digital modulation, contains complementary signals bearing and is located in the first frequency spectrum, and the second and third group of signals carrying subjected to digital modulation, contain complementary signals bearing and are positioned outside of the first frequency spectrum. The method consists in the fact that they are subjected to the first fast Fourier transform digital broadcast signal that is compatible with the amplitude-modulated signal to generate the first converted signal representing complementary bearing; process the first converted signal for the formation of the first adjusted signal by multiplying the first transformed signal to the first adjustment vector, and the first adjustment vector formed by the first set of correction coefficients; updating the first set of correctly with amplitude-modulirovannym signal, for forming the second converted signal representing the complementary bearing; determine a second correction vector formed by the second set of correction coefficients, the second set of correction coefficients determined by interpolation of the coefficients of the first population of correction coefficients and process the second converted signal for forming a second corrected signal by multiplying the second converted signal to the second correction vector.

The invention also covers the operation of radios, which use the above method, and, in addition, the device operating under the above described method, and radios, which use the above method.

BRIEF DESCRIPTION of DRAWINGS in order that the specialists in this field of technology was more understandable to the invention, the following description provided with reference to the accompanying drawings, in which: Fig. 1 is a diagram representing a composite signal consisting of a digital broadcast signal and an analog AM signal, corresponding to the prior art; Fig.2 is a block diagram of the receiver, which may what which illustrates the action of the demodulator and adaptive corrector in accordance with the present invention; Fig.4A and 4b is a vector diagram illustrating the invention; Fig. 5 is a chart illustrating the amplitude-frequency characteristic corrector.

A DETAILED DESCRIPTION of the PREFERRED embodiments
The present invention provides a method of demodulation and correction of bearing in the broadcast signal, which contains the analog amplitude-modulated signal and a digital signal for transmission which uses the same scheme, channel assignment, and that the existing analog AM broadcasting. A method of broadcasting a digital signal on the same channel used for transmission of analog AM signal, called broadcasting in the frequency band of the main channel (ITOOK). This broadcast is carried out by passing the digital signal through the aggregate carrying modulated format MOCR, and some of them are modulated in quadrature with respect to the analog AM signal and placed in the spectral region in which the analog AM broadcast signal has significant energy. The remaining carrying a digital signal modulated in phase and in quadrature with respect to the analog AM signal and are placed on the same channel as the analog AM signal, but in the spectral is the Scripture of the Federal communications Commission (FCC) radiation radio stations broadcasting in the AM band, subject to the mask signal, which is specified as follows: the level of radiation in the frequency bands located on either side of the carrier for analog signal in the range from 10.2 to 20 kHz should be at least 25 dB below the unmodulated analog carrier signal, the level of radiation in the frequency bands located on either side of the carrier for analog signal in the range from 20 to 30 kHz should be at least 35 dB below the unmodulated analog carrier signal and the level of radiation in the frequency bands, located on both sides of the carrier for analog signal in the range from 30 to 60 kHz should be at least 35 dB + 1 dB/kHz below the level of the unmodulated analog carrier signal.

In Fig. 1 presents the range of the broadcast signal of the digital audio signal and the amplitude-modulated signal, similar to that used in accordance with the present invention. Curve 10 represents the standard broadcast signal with amplitude modulation, the carrier which has a frequency f0. Mask radiation prescribed by the FCC, represented by position 12. Waveform format MOCR formed near the bearing data, exploded ntire bearing, subjected to digital modulation, is placed in the frequency band from f0-12f1to f0+12f1that illustrates the envelope, indicated in Fig. 1 position 14. The level of most of these signals are reduced by 39.4 dB relative to the signal level of the unmodulated carrier of the AM signal, in order to minimize crosstalk with analog AM signal. To further reduce crosstalk apply this encoding digital information, which ensures orthogonality with respect to the signal waveform corresponding to the shape of the analog AM signal. This kind of encoding is called complementary coding (i.e., complementary DFMN (binary phase shift keying), complementary CPMN (quadrature phase shift keying) or complementary 32-Noah QAM (quadrature amplitude modulation) and described in more detail in the previously discussed thoroughly review the application 08/671252. Modulation format complementary DFMN used for the inner pair of bearing a digital signal f0f1to facilitate the recovery of the synchronization. The levels of these bearing set equal to -28 DBs. All other carriers belonging to this first group of 48 and 32 kbit/s 8-Naya FMN is used to modulate the carrier in the range of f0-11f1to f0-2f1from f0+2f1to f0+11f1for the coding rate 16 kbit/s Bearing f0-12f1and f0+12f1serve to transfer assistance data and can be modulated using complementary 32nd CAM for all three velocity encoding.

Additional groups carrying digital signals are placed outside of the first group. The need in quadrature relation between these forms of digital signals and the analog signal is removed by limiting the frequency band of the analog AM signal. Bearing the second and third groups covered envelopes 16 and 18, respectively, can be modulated using, for example, a 32-Noah CAM for speeds of 48 and 32 kbit/s and 8-s QPSK for speed 16 kbit/s For all speeds of coding levels bearing set equal to -30 DBs.

In Fig. 2 depicts a block diagram of a receiver intended to receive the composite analog and digital signals, shown in Fig.1. The antenna 110 receives a composite signal containing digital and analog signals, and sends the signal to the normal input of the cascades 112, which may include re frequency on line 114. The intermediate frequency signal passes through the circuit 116 automatic gain control and generator 118 I/Q signals. The generator I/Q signals generates a common-mode signal on the line 120 and the quadrature signal on line 122. In-phase channel output on line 120 enters the analog-to-digital Converter 124. Similarly, the quadrature channel output on line 122, is supplied to another analog-to-digital Converter 126. The feedback signals on lines 120 and 122 are used to control circuit 116 automatic gain control. The signal on line 120 includes an analog AM signal, which is released as shown by a block 140 and is served in the output stage 142 and then to the loudspeaker 144 or other output unit.

The demodulator 150 receives digital signals on lines 128 and 130, and generates output signals on lines 154. These output signals are sent to the corrector 156, and then in block 158 of the filter data rate and data decoder. To obtain a higher signal to noise ratio (SNR) for the complementary bearing, output signals of the FFT for pairs of complementary bearing unite. The output signal of the decoder data serves to block 164 scheme removal of alternation and decoder for forward error correction for increase in decoder 166 of the original signal. The output signal of the decoder of the source signal subjected to the delay circuit 168 to compensate for the delay of the analog signal in the transmitter and the timing of analog and digital signals at the receiver. The output signal of the delay circuits 168 is converted into an analog signal using a digital to analog Converter 160 for signal Q on line 162, which enters the output stage 142.

In the patent 5559830, issued September 24, 1996, describes one mode of operation of the corrector, which implements the algorithm updates the correction coefficients. The present invention allows to improve the performance of the corrector and the update algorithm of correction coefficients by taking into account the effects that may occur when the correction coefficients are provided by the symmetry of the module or the symmetry of phase with respect to the Central frequency of the FFT.

In Fig. 3 shows a functional block diagram illustrating the processing of the signal produced in the receiver in accordance with the present invention. In-phase (I) and quadrature (Q) signals on lines 128 and 130. These signals can be obtained using the conversion items with decreasing frequency, similar to those ctenophore Fourier (BPF), designated as block 170, it is possible to additionally use a filter 174 of the upper frequencies, which filters the in-phase components of the signal propagating along the line 128, and thus generates a filtered signal on line 148. The signals propagating along the lines 148 and 130 before getting on BPF, are processed in block 171 weighing compactly supported function and removal of the guard interval. You should use this finite weighing function to carry the digital signal remained orthogonal or at least the degree of reorthogonalize between the bearing digital signal was small enough not to degrade the system parameters. Was developed the method of using finite weighing function, which preserves the orthogonality between the carriers. According to a particular implementation variant of the method in the transmitter and receiver are used finite weighing function that has a view of the square root of the cosine. This finite weighing function provides the downturn in the first and the last seven samples of 135 samples that make up the sampling period. After applying finite weighing function in the receiver the last seven samples summed with the first seven samples, with the 129-th selection scheme, until you add 135-th sample to the seventh sample. Received 128 points come on FFT. In some cases it may be useful to perform the operation of weighing compactly supported function and remove guard interval before processing by the filter 174 of the upper frequencies. In this case, the operation of the weighing compactly supported function and removal of the guard interval, through circuits 171 and 173, it is possible to combine the order they were performed by a single schema.

The elimination of the analog signal may be required to prevent penetration of the spectral components of the analog signal in the region of the in-phase component for complementary bearing. The disadvantage of this high-pass filter is that the information necessary for the proper correction and demodulation complementary bearing, may break down when the channel is no symmetry in the amplitude or the symmetry in phase relative to the carrier frequency for the analog AM signal. If removal of the analog signal common-mode input BPF passed through the high-pass filter, the output signal BPF to which is applied the update algorithm of correction coefficients, acquires certain sweybbf has energy close to zero, then the output signal BPF for complementary bearing has a symmetry close to internetowej. The same property is true for the output signal of the decision on the symbols for the complementary carriers. Since the input signals of the update procedure correction coefficients are these two internetowych signal, the amplitude-frequency characteristic corrector must be symmetric, and its phase response is antisymmetric with respect to the Central frequency of the FFT. Therefore, the adjustment factors will not converge to the correct values when the adjustment factors should be asymmetric module or participtation phase with respect to the Central frequency BPF.

Output signals BPF corresponding complementary bearing, proceed along the lines 176 in the first corrector 178. Concealer 178 operates with data in the frequency domain and regulates the amplitude and phase of each carrier subjected to modulation format MOCR, to compensate for the effects of channel disturbances filters in the transmitter and the receiver, the transmit and receive antennas, and other factors that affect the amplitude and fdet on line 184 signals, representing digital information transferred complementarity bearing form of broadcast signal that is compatible with the AM signal.

The information transmitted on lines 176 and 184, are used to update the coefficients of the components of the correction vector in the corrector KOR1, which is carried out in block 186. The coefficients to be applied to the complementary bearing, which handles corrector COR indicated by block 188, determined by interpolation, which is performed in block 190. Input signals 128 and 130 is processed in block 173 weighing compactly supported function and removal of the guard interval, and then served in the processor fast Fourier transform BPF, which generates output signals corresponding to the complementary bearing, and these output signals are sent to the corrector COR on lines 192. The output signal of the offset 156, shown in Fig.2, may be a combination of output signals KOR1 178 and COR 188, shown in Fig.3, or a combination of signals 184 and 202, shown in Fig. 3, depending on what type of data is required for further processing, which may in particular depend on the type of forward error correction (PIO) used in the system. If the s bearing can be achieved combining the output signals of the FFT for pairs of complementary bearing. In particular, the data is transferred through one of the complementary bearing, summarize with paired with the opposite sign data transmitted by other complementary carrier, and then calculate the average value. For each pair of complementary bearing processed by the corrector COR, one of the pair of bearing is subjected to mate with the opposite sign in the block 194 and stack with another carrier pair by adders 196 and 198. Then, the controller 200 characters generates output signals representing digital information transferred through complementary bearing broadcast signal that is compatible with the AM signal.

In Fig. 4A and 4b depicts a vector diagram that can be used as additional illustrations of the invention. In Fig.4A depicts a vector diagram of the transmitted signal. On the horizontal axis lay I-components, while the vertical axis is the Q-components of the signals. The constant level of the carrier of the AM signal represented by the vector 204, oriented along the horizontal axis, and a vector chart is fixed relative to the carrier frequency of the AM signal. In Fig.4A shows also detect the IG.4A shows the resulting signal 210, i.e. the vector sum of the analog side bands. The resulting signal lies on axis I and remains on axis I, while the vectors of the side strips revolve. In Fig.4A also shows the vectors 212 and 214, representing one pair of complementary bearing. The resulting vector 216 these bearing lies on the axis Q and remains on the axis Q at that time, as vectors of complementary bearing spin.

In Fig. 4b presents a vector diagram in the receiver taking into account the fact that the channel is asymmetric in amplitude and neantiomkeren phase. You can see that in this case the energy of the resulting signal 216' complementary pairs 212' and 214' are distributed between the I - and Q-components. If the address of the I signal at the frequency of complementary base pair through a high-pass filter, shown in Fig.3, the signal cannot be properly adjusted and demodulate. Although in Fig. 4A and 4b shows only one pair of complementary bearing, the above calculations are valid for all complementary bearing. Fig. 4A and 4b show another effect that prevents the correct demodulation complementary bearing. The energy of the resulting signal 210' analog side strips 206' and 208' is also distributed between the I - and Q-components. This prep is Nala falls on the Q-component. Therefore, the output signal BPF cannot be used to correct demodulation complementary bearing, when the channel is asymmetric in amplitude and neantiomkeren phase. However, the output signal BPF can be used for correction and demodulation complementary bearing. Because output BPF is used only information transmitted complementarity bearing, it is necessary to calculate output signals only for complementary bearing. According Fig.3 the output signal BPF routed to the first corrector marked KOR1. This concealer as well as the second corrector marked COR, process the frequency data and adjusts the amplitude and phase of the carrier, modulated format MOCR, to compensate for the effects of channel disturbances filters in the transmitter and the receiver, the transmit and receive antennas, and other factors and process that affect the amplitude and phase of the signal. The output signal KOR1 enters the processor solutions for the characters, which determines which of the points of the frequency diversity was passed. These decisions, together with the previously adjusted points of diversity and the previous values of correction coefficients are used to update algorithm, for example the method of least medium squares (MSC) or recursive method medium squares (RMS).

According Fig. 3 BPF used to obtain information transferred complementary bearing. I-signal in BPF not subjected to filtering high frequencies and therefore the output BPF has all of the information necessary for correction and demodulation complementary bearing. Because output BPF uses only the information transmitted by the complementary bearing, it is necessary to calculate only the output signals for the complementary carriers. The output signal BPF correct by CAR. According Fig.3 for each pair of complementary bearing one bearing of the pair is subjected to mate with the opposite sign from the other bearing of the pair. This amount is used for making decisions on the symbols for the complementary pair. The coefficients for CAR can be updated in the same way as for KOR1, but the presence of the analog signal may cause noise estimated values of the coefficients. To avoid this effect, you can get the values of correction coefficients for COR the interpolation method using the conversion factors for KOR1. When properly configured control circuits priema characters the center frequency of the FFT must comply with known constant amplitude and phase.

In Fig.5 shows an example of using linear interpolation for determining corrective coefficients in the field of complementary bearing. In fact, in Fig.5 shows the inverse frequency response of the channel 218, because it should look like frequency characteristic corrector. In Fig.5 shows also feature 220, which can be obtained on the basis of the module output signal of the offset. For clarity, the illustrated characteristic corrector shifted slightly upwards, so that it can be distinguished from the reverse characteristics of the channel. Note that in the regions 222 and 224, responsible complementray sound, characteristic of the offset equal to the inverse characteristic of the channel. From the graph you can see that if the characteristic of the channel 218 is relatively smooth, the interpolated correction coefficients close to the ideal values and the amplitude-frequency characteristic corrector 220 coincides with the inverse frequency response of the channel region 226 complementary bearing.

There may be some other options for the interpolation. For example,container carrier, can be used for linear interpolation of their values to the value at the center of the channel. It was found that linear interpolation gives acceptable results in most cases, when the signal is in-band commercial AM broadcast (from 530 to 1710 kHz), and the width of the region complementary bearing is less than 10 kHz. Alternatively, it may be useful to use complementary bearing, lying farther from the center frequency of the channel, if one or more complementary bearing, lying near the area of complementary bearing, are filtered, for example through high-pass filters that can be used to eliminate the analog signal of the inphase component of the received signal. In addition, the interpolation process can use the information moving numerous complementary bearing. You can use interpolation algorithms, non-linear. As examples of well-known interpolation algorithms can lead to interpolation using cubic spline, polynomial interpolation, interpolation based on the FFT and the approximation of exponential or logarithmic curve. Caracterizati for complementary bearing, obtained by interpolation, can be averaged over time to reduce noise impacts. To reduce the impact of noise can also use the aliasing frequency. Instead of interpolation modules of the coefficients in the linear scale may be preferable to interpolate the amplitude in logarithmic scale. Alternative instead of interpolate module and phase correction coefficients, it may be useful to interpolate the corresponding real and imaginary components of the coefficients (Cartesian coordinates), which can also be used to represent correction coefficients.

The invention proposes a system for demodulation and adaptive correction signal broadcast digital audio compatible with amplitude-modulated signal. In the above description set forth certain preferred options for implementation and enforcement of this invention, however, it should be understood that other embodiments of the invention within the scope of the invention defined in the following claims.


Claims

1. The way demodulation and correction Rowany RF signal, having the first carrier, the modulated analog signal of the program in the first frequency spectrum, a set of signals carrying subjected to digital modulation posted in the frequency band covering the first frequency spectrum, and the first group of signals carrying subjected to digital modulation, contains complementary signals bearing and is located in the first frequency spectrum, and the second and third group of signals carrying subjected to digital modulation, contain complementary signals bearing and are positioned outside of the first frequency spectrum, which is subjected to fast Fourier transform digital broadcast signal that is compatible with the amplitude-modulated signal, for the formation of the first converted signal representing complementary bearing, characterized in that the handle of the first transformed signal for the formation of the first adjusted signal by multiplying the first transformed signal to the first adjustment vector, and the first adjustment vector formed by the first set of correction coefficients, updating the first set of correction coefficients used for nExample odno-modulated signal, for forming the second converted signal representing the complementary bearing, determine the second correction vector formed by the second set of correction coefficients, the second set of correction coefficients determined by interpolation using the first coefficients of the totality of correction coefficients, and process the second converted signal for forming a second corrected signal by multiplying the second converted signal to the second correction vector.

2. The method according to p. 1, characterized in that share a digital broadcast signal that is compatible with the amplitude-modulated signal, in-phase and quadrature components and filtered in-phase component of the digital broadcast signal that is compatible with the amplitude-modulated signal, before a fast Fourier transform implemented on a digital broadcast signal that is compatible with the amplitude-modulated signal to generate the first converted signal.

3. The method according to p. 2, characterized in that when filtering the in-phase component missing in-phase component through a high-pass filter.

4. The way p is borovany signal, and removes the guard interval from the digital broadcast signal that is compatible with the amplitude-modulated signal, each of the operations of the fast Fourier transform performed on a digital broadcast signal that is compatible with the amplitude-modulated signal.

5. The method according to p. 1, characterized in that the second set of correction coefficients calculated by using the first aggregate correction coefficients and the known values for the center frequency of the first frequency spectrum, and the calculation is performed by interpolation using linear interpolation, interpolation using a cubic spline, polynomial interpolation, interpolation based on the fast Fourier transform or approximation of a logarithmic curve.

6. The method according to p. 1, characterized in that the interpolation is done with an averaging time.

7. The method according to p. 1, characterized in that the interpolation carried out on the real and imaginary components used to represent the first and second sets of correction coefficients.

8. The method of operation of a radio receiver for receiving digital broadcast signal that is compatible with amplitude-modulated is ing analog signal of the program in the first frequency spectrum, the set of signals carrying subjected to digital modulation posted in the frequency band covering the first frequency spectrum, and the first group of signals carrying subjected to digital modulation, contains complementary signals bearing and is located in the first frequency spectrum, and the second and third group of signals carrying subjected to digital modulation, contain complementary signals bearing and are positioned outside of the first frequency spectrum, namely, that receive a digital broadcast signal that is compatible with the amplitude-modulated signal, and subjected to fast Fourier transform digital broadcast signal that is compatible with the amplitude-modulated signal, for the formation of the first converted signal representing complementary bearing, characterized in that the handle of the first transformed signal for the formation of the first adjusted signal by multiplying the first transformed signal to the first adjustment vector, and the first adjustment vector formed by the first set of correction coefficients, updating the first set of correction coefficients used for complementary is included in the signal, for forming the second converted signal representing the complementary bearing, determine the second correction vector formed by the second set of correction coefficients, the second set of correction coefficients determined by interpolation using the first coefficients of the totality of correction coefficients, process the second converted signal for forming a second corrected signal by multiplying the second converted signal to the second correction vector and generate an output signal in accordance with the first and second adjusted signals.

9. The method according to p. 8, characterized in that share a digital broadcast signal that is compatible with the amplitude-modulated signal, in-phase and quadrature components and filtered in-phase component of the digital broadcast signal that is compatible with the amplitude-modulated signal, before a fast Fourier transform implemented on a digital broadcast signal that is compatible with the amplitude-modulated signal to generate the first converted signal.

10. The method according to p. 9, characterized in that when filtering the in-phase with the fact, that weigh a compactly supported function digital broadcast signal that is compatible with the amplitude-modulated signal, and removes the guard interval from the digital broadcast signal that is compatible with the amplitude-modulated signal, each of the operations of the fast Fourier transform performed on a digital broadcast signal that is compatible with the amplitude-modulated signal.

12. The method according to p. 8, characterized in that the second set of correction coefficients calculated by using the first aggregate correction coefficients and the known values for the center frequency of the first frequency spectrum, and the calculation is performed by interpolation using linear interpolation, interpolation using a cubic spline, polynomial interpolation, interpolation based on the fast Fourier transform or approximation of a logarithmic curve.

13. The method according to p. 8, characterized in that the interpolation produce averaged over time.

14. The method according to p. 8, characterized in that the interpolation carried out on the real and imaginary components used to represent the first and second sets of correction coefficients.

15. Remove the scrap, containing amplitude-modulated RF signal having the first carrier, the modulated analog signal of the program in the first frequency spectrum, a set of signals carrying subjected to digital modulation posted in the frequency band covering the first frequency spectrum, and the first group of signals carrying subjected to digital modulation, contains complementary signals bearing and is located in the first frequency spectrum, and the second and third group of signals carrying subjected to digital modulation, contain complementary signals bearing and is located outside of the first frequency spectrum containing the means (170) fast Fourier transform of the digital broadcast signal, compatible with amplitude-modulated signal to generate the first converted signal representing complementary bearing, characterized in that it contains means (178) processing the first transformed signal for the formation of the first adjusted signal by multiplying the first transformed signal to the first adjustment vector, and the first adjustment vector formed by the first set of correction coefficients, the means (186) on the tool (172) fast Fourier transform of the digital broadcast signal, compatible with amplitude-modulated signal to generate the second converted signal representing the complementary bearing, means (190) determining a second correction vector formed by the second set of correction coefficients, and for determining a second aggregate correction coefficients tool interpolates the coefficients of the first population of correction coefficients, and means (188) processing the second converted signal for forming a second corrected signal by multiplying the second converted signal to the second correction vector.

16. The device according to p. 15, characterized in that it contains means (118) separation complementary signals bearing on the in-phase and quadrature components and the means (174) filtering the in-phase component complementario of the carrier signal.

17. The device according to p. 16, characterized in that the filtering means includes a high-pass filter.

18. The device according to p. 15, characterized in that it contains means (171, 173) weighing compactly supported function digital broadcast signal that is compatible with the amplitude-modulated signal, and remove guard interval iisalmen fact, to calculate a second population of correction coefficients used by the first set of correction coefficients and the known value for the center frequency of the first frequency spectrum, and the calculation is performed by interpolation using linear interpolation, interpolation using a cubic spline, polynomial interpolation, interpolation based on the fast Fourier transform or approximation of a logarithmic curve.

20. The device according to p. 15, characterized in that the interpolation is accompanied by averaging over time.

21. The device according to p. 15, wherein the interpolation is performed on the real and imaginary components used to represent the first and second sets of correction coefficients.

22. A radio receiver for receiving digital broadcast signal that is compatible with the amplitude-modulated signal containing amplitude-modulated RF signal having the first carrier, the modulated analog signal of the program in the first frequency spectrum, a set of signals carrying subjected to digital modulation posted in the frequency band covering the first frequency snali bearing and is located in the first frequency spectrum, and the second and third group of signals carrying subjected to digital modulation, contain complementary signals bearing and are positioned outside of the first frequency spectrum containing the means (170) of the fast Fourier transform digital broadcast signal that is compatible with the amplitude-modulated signal to generate the first converted signal representing complementary bearing, characterized in that it contains means (110) for receiving a digital broadcast signal that is compatible with the amplitude-modulated signal, means (178) processing the first transformed signal for the formation of the first adjusted signal by multiplying the first transformed signal to the first adjustment vector, the first adjustment vector formed by the first set of correction coefficients, the means (186) updates the first population of correction coefficients used for complementary signals, means (172) fast Fourier transform of the digital broadcast signal that is compatible with the amplitude-modulated signal to generate the second converted signal representing the complementary bearing, means (190) determine W the La to identify a second population of correction coefficients tool interpolates the coefficients of the first population of correction coefficients, means (188) processing the second converted signal for forming a second corrected signal by multiplying the second converted signal to the second correction vector, and means (142) generate an output signal in accordance with the first and second adjusted signals.

23. Radio on p. 22, characterized in that it contains means (118) separation complementary signals bearing on the in-phase and quadrature components and the means (174) filtering the in-phase component complementario of the carrier signal.

24. Radio on p. 23, characterized in that the filtering means includes a high-pass filter.

25. Radio on p. 23, characterized in that it contains means (171, 173) weighing compactly supported function digital broadcast signal that is compatible with the amplitude-modulated signal, and remove guard interval from the digital broadcast signal that is compatible with the amplitude-modulated signal.

26. Radio on p. 23, wherein to calculate a second population of correction coefficients used by the first set of correction coefficients and the known value for the center frequency of the first of dastoli, interpolation using cubic spline, polynomial interpolation, interpolation based on the fast Fourier transform or approximation of a logarithmic curve.

27. Radio on p. 23, characterized in that the interpolation is accompanied by averaging over time.

28. Radio on p. 23, characterized in that the interpolation is performed on the real and imaginary components used to represent the first and second sets of correction coefficients.

 

Same patents:

The invention relates to radio broadcasting and can be used for correction of the demodulated signal at the receiver is designed to work in the system broadcast a digital signal that is compatible with the amplitude-modulated signal

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FIELD: methods and devices for processing composite audio broadcast signal.

SUBSTANCE: proposed method includes following procedures: analog-modulated part of audio broadcast signal is separated from digital-modulated part of audio broadcast signal; data from analog component of broadcast signal is separated from its digital component to produce mixed output audio signal. Method is also proposed for transferring composite audio broadcast signal that has analog part and digital part to suppress irregular interruptions in reception of mentioned audio broadcast signal by adding modem frames with analog part of broadcast signal which incorporate audio frames presenting digital part of audio broadcast signal.

EFFECT: provision for suppressing irregular interruptions in reception of audio broadcast signal.

25 cl, 4 dwg

FIELD: control data transmission in audio broadcast.

SUBSTANCE: proposed method includes transmission phases for transferring set of control bits in each of set of control frames, first control bit sequence presenting transmission mode and second one, control data synchronizing word. Set of control bits may include in addition third sequence of bits presenting interleaver synchronizing word. Method for detecting mode of transmission and synchronization of audio broadcast signal implemented in radio receiver is also proposed. This method includes reception phases for set of interleaver frames incorporating digital information, each of interleaver frames incorporating set of control frames. Control frames include set of control bits; first sequence of control bits presents transmission mode and second one, control data synchronizing word. Set of control bits may include in addition third bit sequence presenting interleaver synchronization word. First sequence of control bits is processed for definite transmission mode, second one, for detecting control data synchronization, and third sequence of control bits, for determining interleaver boundaries. Radio-frequency transmitters and receivers using above-described methods are also given in description of invention.

EFFECT: reduced cross-talk noise with respect to analog amplitude-modulated signal.

12 cl, 5 dwg

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