Method and device for improved noise immunity
The invention relates to radio communications. The technical result consists in increasing the stability of the receiver to interference. Capacity (M) of the received signal (1702) is governed by the enabling or blocking low-noise amplifier (LNA) depending on the measured values M of the received signal (1704). The received M periodically compared to the threshold (1704). If the received level M more than the threshold value, then the LNA is blocked. LNA is released when the received M becomes smaller than the threshold (1708), and not found significant intermodulation components (IP) (1710). IP detected by brief enable LNA and detecting changes in the measured M signal (1710). If the detected change exceeds a predetermined value, then there are significant IP and LNA is not enabled (1706). Otherwise, significant IP and no LNA is released. 2 C.p. f-crystals, 17 ill. 1. The technical field to which the invention relates the Present invention relates to radio communications. More specifically, the present invention relates to an improvement in the stability of the coherent receiver to interference during communication.2. Prior art Exists mnozhestvenoe (storing UMTS) and two digital cellular systems: multiple access with time division multiplexing (mdvr) and multiple access, code-division multiplexing (mdcr). Digital cellular systems provide a solution to the problems associated with bandwidth, inherent in the system storing UMTS.All cellular radiotelephone systems use multiple antennas covering a geographical area. Antennas radiate in the area called cell. Cells storing UMTS separate and distinct from the cells mdcr. This may cause the antenna to a cell of one system may be in the cell of the other system. Within a particular system (storing UMTS, mdcr or MDR) may also exist two service provider of the communication in this area. These providers often prefer to place cells in geographical areas other than their competitor. Therefore, there are situations in which a radio telephone system And may be located far from the nearest cell system and at the same time close to the cell system Century. This situation means that the useful received signal will be weak in the presence of strong multi-frequency interference.This crossing of the antenna system can cause problems for your mobile phone, which is registered in one system, such as system mdcr, and moves around another antenna system, such as storing UMTS antenna. In this case, the signals from the antenna the high-power signal is a direct line of communication storing UMTS.Multi-frequency interference, accidentally accept the phone from the signal storing UMTS, creates a distortion or receiving spurious signals. If they fall within the range used by the phone mdcr, they can impair the operation of the receiver and demodulator.It often happens that the system is storing UMTS creates unintentionally causing the system to rival carriers (a and b ranges). The task of the carrier frequency cell system is to ensure a high signal - to-noise (S/N) for all users of the respective systems by placing cells near or next to their users and radiation power allowed by the Federal communications Commission (FCC), for each channel storing UMTS. Unfortunately, this technique provides the best signal quality for bearing the cost of interference with the system competitor.Intermodulation distortion, such as caused by the above situation, are defined in terms of peak level of spurious signals generated by two or more tone signals in the receiver. Most often, the level of distortion of the third order for the receiver is defined as "the interception point (receive) input third order or TPVS. TPWS is defined as the input power (Noi power of the two tones. As shown in Fig.13, TPVS can be linearly extrapolated only when the nonlinear element, such as the amplifier is below the threshold of saturation.As shown in Fig.14, the distortion of the third order occurs when two tone signal received in the receiver. Tone #1 has a frequency fl at power level P1, expressed in dB per mW. Tone #2 has a frequency f2 at power level P2, expressed in dB per mW. As a rule, set P2 is equal to P1. The distortion of the third order will be created when the frequency 2*f1-f2 and 2*f2-f1 when the level of capacity R and P21, respectively. If P2 is set to P1, then the parasitic components must be equal to or R and P21 must be equal. The signal fc is entered at power levels of RS, to show that the added distortion is a low level signal. If you have a filter that filters f1, f2 and f21 after it was created distortion, then the power at frequency f12 will continue to interfere with the signal frequency fc. For example, in Fig.14, with respect to MTCR, the problem is that intermodulation component R should be equal to the signal power - 105-dB / mW, for a total capacity of two tone - 43 underwater nonlinear element is defined as follows: CPUS = +Pin(dB / mW) If P1= P2then Pin= P1+3dB or R2+3dB (dB / mW) and IM3=P1-P12= P2-R21= P2-P12= P1-R21(dB) For cascade CPUS that uses more non-linear elements, the expression is as follows: CPUS = -10log10[10(Gain-TPVS)/1010+(-TPVSbeforeIdumea)10] where Gain = gain on the input element.Therefore, one way to improve cascade TPVS receiver is to reduce the gain before the first nonlinear element. In this case, a low noise amplifier (LNA) and a frequency Converter limit TPVS. However you want to define another quantity, which determines the sensitivity or lower limit of the received signal without interference. This value engineering is defined as the ratio of noise (CABG). If the receiver gain is reduced to improve CPUS (and immunity to interference), CABG (and sensitivity to small useful signal) is reduced.For elements in the cascade in the receiver expression takes the form
where CSethe noise factor of the item
CSi- cascade noise figure of the cascade CS can be achieved, if the gain up to the corresponding element is maximized, which is in contradiction with the requirement of "best" cascade TPVS. For CABG within this element and receiver and for TPVS there is a limited set of gain values for each element, which satisfy all requirements.Typically, the receiver design with CABG and TPVS as predefined constants, since both these quantities define the dynamic range of the receiver taking into account interference and without interference. Strengthening adult and TPWS optimize each device on the basis of size, cost, power consumption, thermal, static and active current element. In the case of a dual mode portable cellular receiver system mdcr and FM (frequency modulation) standard mdcr require CABG, equal to 9 dB at the minimum signal. In other words, mode mdcr requirement of sensitivity corresponds to a ratio of 0 dB at - 104 dB / MW. For FM mode this requirement corresponds to a ratio equal to 4 dB at -116 dB / mW. In both cases, the requirements can be transferred to the CS as follows:
CS = S (dB / mW) - -Ntherm(dB mW/Hz) Signal BW (dB/Hz),
where S is the minimum signal power for meal BW (dB/Hz) is the bandwidth of the signal.So mdcr CS = -104 dB mW, 0 dB(-174 dB mW/Hz)-61 dB/Hz = 9dB,
FM CS = -116 dB at mW-4 dB-(-174 dB mW/Hz)-45 dB/Hz = 9dB,
where -61 dB mW/Hz noise frequency band for mdcr channel
- 45-dB / mW/Hz noise frequency band for FM channel.However, CABG receiver must be taken into account only when the signal is close to the minimum level, and TPVS only in the presence of interference or MARK signals high power.There are only two ways to provide coverage in areas where the carrier creates a strong barrier. One solution is to use the same technique, i.e., to have their cells together with cells of a competitor. Another solution is to increase the stability of the receiver to interference. One of the ways to improve the stability of the receiver is to increase the amperage. It is, however, not acceptable for portable devices radio, which uses the battery power supply. The increase in current will result in a more rapid consumption of battery power and, consequently, reduction of communication time and operation time of the apparatus is in the standby mode. Thus, there is a need to minimize the radio frequency interference without changes in the current consumption.The ESSENCE of Every circuit, to improve the robustness of the receiver to interference. This loop contains a LNA which amplifies the received signal. The power of the received signal to control the on or lock LNA in accordance with the value of the measured power of the received signal. The level of the received power is periodically compared with a threshold value. When the level of the received power is more than the threshold value, LNA block. LNA will unlock when the level of the received power is less than the threshold value, and is not found significant intermodulation components.Intermodulation components found in the quick release LNA and detecting changes in the measured signal power. If a change is detected is greater than a predefined value, then there are significant intermodulation components and LNA not will unlock. However, if the detected change is less than a predefined value, then there are minor intermodulation components and LNA will unlock.BRIEF DESCRIPTION of DRAWINGS
Fig. 1 is a functional diagram of the device corresponding to the present invention to improve the stability of the receiver;
Fig.2 - Naya diagram of an alternative implementation of the present invention;
Fig.4 is a functional diagram of an alternative implementation of the present invention;
Fig. 5 is a graph of the relationship of carrier to noise depending on the input radio-frequency (RF) power in accordance with the embodiment of Fig.7;
Fig. 6 is a graph of the relationship of carrier to noise depending on the input radio-frequency (RF) power in accordance with the embodiment of Fig.8;
Fig.7 is a functional diagram of an alternative implementation of the present invention;
Fig.8 is a graph of interference power depending on the signal strength without the use of a device corresponding to the present invention;
Fig.9 is a graph of interference power based on the power signal in accordance with an alternative embodiment of the device corresponding to the present invention;
Fig.10 is a functional diagram of an alternative implementation of the present invention;
Fig. 11 is a functional diagram of an alternative implementation of the present invention;
Fig. 12 is a functional diagram of an alternative implementation of the present invention;
Fig. 13 is a graph of measured values of the nonlinear transfer characteristics and distorted the distribution power of the received signal in accordance with the present invention;
Fig.16 is a block diagram of the process of adjusting the gain in this invention;
Fig. 17 is a block diagram of the process gain in an alternative embodiment of the present invention.The present invention is the change in CS and TPWS receiver to improve CPUS (or resistance to interference), without risk for CABG, when you need it. This "improvement" work is accomplished by changing the gain of the first active element in the receiver. The gain can be varied by changing the gain LNA in a continuous range or off of a low noise amplifier with bypass switch.Functional diagram of the preferred alternative implementation of the present invention shown in Fig.1. This alternative implementation uses the setting of the gain of LNA 115 on a continuous basis, using a custom controller 110 gain (ANR) in the input stages of the receiver. Continuous ANR 110 in the input stages of the receiver provides the advantage of linearity at the minimum RF level at the input, while ANR 120 on the transmission side can reduce the requirements for ANR 125 and 130 on the intermediate frequency (if).Consider an implementation option definition the e on RF. In this embodiment, the detector 105 power can continuously reduce the gain LNA 115 when the values of the received power is below a value of 65 dB (mW/Hz, which is used in subsequent versions of the implementation with switchable gain, shown in Fig.7, Fig.10, Fig.11 and Fig.12.In a preferred embodiment, the detector 105 power defines the power of the received signal and the active interference of the RF. Received power passes through the low pass filter synchronous detector and is used to configure the receiving ANR 110, thus adjusting the point of reception of the receiving device components. The gain is reduced when the measured power is growing, and the gain is increased when the measured power is reduced. This alternative implementation may also be combined LNA 115 and ANR 110 to create a LNA with variable gain, thus avoiding the need for a separate unit ANR 110. The power transmitting ANR 120 located at the front of the amplifier 150 power is regulated in the same way as the power receiving ANR 110 in order to maintain the overall level of transmitted power.The amplifiers 125 and 130 with the NAO are after a converters 135 and 140 frequency to regulary 125 and 130 ANR perform regular system mdcr adjustment function power open circuit, power control in a closed loop and compensation. FC ANR 125 and 130 are necessary because of the requirements of a wide dynamic range for the system mdcr. Typically, such ANR 125 and 130 have a gain range over 80 dB. Receiving and transmitting ANR 125 and 130 after frequency converters are configured by another detector 150 power, which measures the total power after the received signal has been converted to a lower frequency. The detector 150 power lowers the strengthening of the NAO 125 and 130, when the power of the signal, converted to a lower frequency, increases, and improves the strengthening of the NAO 125 and 130, when the power is converted to a lower frequency signal is reduced.In a preferred embodiment, the received signals are in the frequency band 869 - 894 MHz. The transmitted signals are in the frequency range 824 - 849 MHz. Alternative embodiments of use of different frequencies.The graph shown in Fig.5 illustrates the advantages of this approach using ANR. The left Y-axis shows the ratio of carrier to noise depending on the received input power, and the parameter is the level of active interference. The right Y-axis shows the total capacity and the override input power. If there is no interference (-100 dB mW/Hz), the radio communications device operates as if no RF ANR. When the active noise increases, the C/N decreases, but the actual linearity increases. In the above example, the dynamic range of the RF equal to 30 dB, and the threshold at which RF NAO becomes active, corresponds to the point at which the active interference power is greater than -25 dB mW/Hz.An alternative implementation of the method of continuous gain setting is illustrated in Fig.2. In this embodiment, the active noise are filtered by the bandpass filter 205 before the detector 210 power determines the power level converted to a lower frequency signal. The threshold detector 225 detects when the power level of the signal reaches a certain value, in this embodiment, it -105 dB (mW/Hz, and then lowers the strengthening of the NAO 230 and 235, while the signal power exceeds the power level. If the power level of the signal falls below this threshold, the strengthening of the NAO 230 and 235 is increased. The strengthening of the NAO 215 and 220 after the converters 240 and 245 frequency is adjusted continuously without checking for a pre-set threshold value, the power and the implementation shown in Fig.6. If the threshold value is set to -105 dB (mW/Hz, corresponding to the minimum level of the received RF signal, the C/N ratio does not grow as fast as in the absence of RF ANR. The advantage of this alternative implementation is that the gain in linearity begins at a very low RF input power, without the need for detector the received RF power, and the ANR circuit detects only the signal power. Therefore, the ANR circuit is simpler than determining RF power.Another variant implementation of the present invention shown in Fig. 3. This implementation works similarly to variant implementation, shown in Fig.1. The only difference is the placement of the ANR LNA 301 to 305 in the receiving path.Another variant implementation of the present invention shown in Fig. 4. In this embodiment, is used attenuator 405 between the antenna duplexer 410 and 415. Insertion attenuation is governed by the detector 420 power is turned on after LNA 425. The detector 420 power measures the power of the received signal and the active interference filters and compares it with a preset threshold value. In this embodiment, the threshold venicebridge, introduced by the attenuator 405 increases. This configuration can be either fixed values in digital form, or continuously. ANR 430 and 435 after frequency inverters 440 and 445 are configured in the same way as in the preferred embodiment, shown in Fig.1.An alternative implementation of the device corresponding to the present invention, shown in Fig.7. In this embodiment, use the switches 701 and 702 for changing the gain of the input stages.The actual level of switching depends on the ratio of signal to noise as a function of signal level or noise factor, for the special design of the cordless telephone system mdcr. The present invention can be used in the phone system storing UMTS, however, the characteristics of the switch will change to match different working points.Consider an implementation option contains the antenna 725, which receives and transmits radio signals. The receiving and transmitting paths in the radio communications device associated with the antenna 725 through the duplexer 720, which separates the received signals from the transmitted signals.The received signal enters the ERU 720, the second switch 702 connects LNA 703 to the band-pass filter 704. In a preferred embodiment, the switches 701 and 702 are single pole GaAs switches on the two positions.LNA 703 is connected to one pole of each switch so that when both switches 701 and 702 are connected to these poles, then the received signal LNA 703 and the amplified signal from LNA 703 goes to the band-pass filter 704. Band-pass filter 704 in this embodiment, has a frequency band 869 - 894 MHz. In alternative embodiments, the implementation uses a variety of ranges depending on the frequency of received signals.The bypass path is connected to the other pole of each switch. When the switches 701 and 702 are installed in a different position, the received signal from the duplexer 720 bypasses the LNA 703 and enters the band-pass filter 704. In this embodiment, these switches 701 and 702 are controlled by the microcontroller of the apparatus 740. In an alternative embodiment, to control these switches use a separate controller. Optionally, in other embodiments, implementation of the bypass tract 730 may be weakening.After bandpass Phi is lower if frequencies for use by other components of the device radio. Conversion with decreasing frequency is carried out by mixing 705 of the received signal with another signal having a frequency determined by the circuit 707 phase of the automatic frequency control (PLL), which is controlled by the generator 706, a voltage controlled. This signal is amplified 750 before entering the frequency Converter 705.Converted to a lower frequency signal from the frequency Converter 705 is fed to the UPR 708 and 709. Consider the UPR 708 and 709 are used by the apparatus for power control in a closed loop, as is known from the prior art.In accordance with the method of the present invention the microcontroller 740 controls the power of the received signal. When power exceeds -65 dB (mW/Hz, the microcontroller 740 instructs the switches 701 and 702 to connect to the bypass position, thus feeding the received signal directly to the band-pass filter 704. Bypassing the LNA gain 703, the point of reception of the receiver increases in proportion to the decrease in gain in dB. In alternative embodiments, the implementation used other schemes and methods for power control of the received signal.In an alternative embodiment of the present invention usoroh power, such as -25 dB mW/Hz.Graphs in Fig.8 and Fig.9 show the advantages of embodiments of the present invention with switchable gain, shown in Fig.7, Fig. 10, Fig.11 and Fig.12. In Fig.8 shows a graph of the interference power depending on the power of the RF signal for normal device radio that does not use equipment switchable gain. This graph shows that the maximum level of interference is limited by the compression at the receiver input when -10.5 dB mW/Hz. The chart shows both curves power: single and dual tones.Graph of Fig.9 shows the interference power based on the power of the RF signal received by the radio communications device using the method switchable gain and the device of the present invention. You can see that in the point graph -65 dB mW/Hz switches are connected to the bypass tract, thus allowing more power interference without affecting the power of the RF signal. The graph shows two curves power: for single and dual tones.An alternative implementation of the device of the present invention shown in Fig.10. In this embodiment, used is and the power of the received signal reaches -65 dB mW/Hz. Thus, the signal is directly fed to band-pass filter 1003, excluding the gain LNA 1002.Another alternative implementation of the present invention shown in Fig. 11. In this embodiment, applies a single-pole switch 1105, which, when closed, grounds through the resistor 1101 LNA input 1110. This creates an inconsistency full resistance at the input, causing signal attenuation, thereby lowering the gain generated by the LNA 1110. As in the above embodiment, the switch 1105 is closed when the input power reaches -65 dB mW/Hz. Active resistance for resistor 1101 depends on the desired attenuation. It will be different for different LNA in an alternative implementation options.Another option exercise device of the present invention shown in Fig. 12. In this embodiment uses a single pole switch 1201 in two directions at the output of LNA 1205. To one pole of the switch 1201 is connected LNA 1205, to the other pole is connected to the bypass path 1210. The entrance to a roundabout path 1210 is connected to the input of LNA 1205. When the power level of the received RF signal reaches -65 dB (mW/Hz, pereklyuchat signal is directly fed to the bandpass filter 1220, bypassing the LNA gain 1205.In all the above embodiments, the implementation can reduce the power LNA at that time, when using the bypass path through the switch or switches.Reducing power can be achieved by connecting pin power LNA with a switch that is controlled by the controller. In the case when the LNA after crawling is no longer used, you can reduce the power that lowers the power consumption of the device Radiocommunication, thus increasing the spoken time and time in standby mode, when you can use the battery life.In another embodiment of the present invention to determine when to adjust the gain in the input stage uses the value of Ewith/Iabout. In additional embodiments, the implementation used other qualitative measurements, such as Eb/Iabout.These relations are qualitative measurements for digital communication systems. The ratio of Eb/Iaboutexpresses the ratio of the power per bit to total spectral density of the interference channel, while the ratio of Ewith/Iaboutexpresses the ratio of the power element code against the which characterizes the work of one communication system over another; the smaller the desired Eb/Iaboutthe more efficient the processes of modulation and demodulation for a given error probability. It is known that Ec/Iaboutand the power of the received signal is easily accessible, the microcontroller can detect the presence of strong interference, as the decline in the value of Ec/Iabout, while the detector ANR detects the increased interference.The microcontroller can lower the gain in the input stage, to improve resistance to interference, which, in turn, should improve the Ec/Iaboutand lower distortion components that fall within the bandwidth of the signal.When the signal rises above threshold Ec/Iaboutor Eb/Iaboutthe gain in the input stage is reduced. Gain control can be carried out using the method of continuous configuration or method of switching amplifier as disclosed above.In another embodiment, shown in Fig.15, is determined by the signal power at the if or the band modeling of signals, instead of defining a joint power signal and the active interference of the RF. This approach is simpler because it uses only one power detector and consti received signals. First, the signal is converted to a lower frequency to frequency 1501 strip group frequencies. This analog signal is then converted into a digital signal 1505 for further processing of the strip group of frequencies, including the determination of the intensity of received signals. Code correlator 1510 determines the power on code element with respect to power all incoherent components. This information together with the indicator of the intensity of received signals (IIPS) is used by the processor 1515 to determine the value of the gain setting and the power receiving 1520, and power transmission 1530.Because the value of the power measurement of the received signals includes the value of the signal strength and the thickness of the active interference accept strengthening grows only when both the signal level and the power element code fall. Because IIPS changed to compensate for the transmit power must also be changed accordingly allowing power control open loop to work properly. Thus, the processor adjusts the gain of the transmission when the received gain configured.In another embodiment, to control the variable gain ANR is used MJ, and accept the power use management only accept power. In Fig.16 presents a method of gain control for both of the above embodiments. This method is based on the relationship shown in the graph of Fig. 13, where you can see that when the interference power at the input increases along the X-axis, intermodulation components (lower curve) are growing faster than the capacity of interference. Therefore, the input X dB of attenuation will decrease intermodulation components 3X dB, if the input of the receiver there is interference.Usually because of its low power, intermodulation components do not fall into the if radio communication devices. Outside the if radio communication devices intermodulation components do not cause problems in the operation of the receiver. Thus, the gain of the receiver is only required when the intermodulation components in a fairly large extent affect the if signal.Referring to Fig.16, it can be seen that in accordance with the method of the present invention, first adjust the input gain 1601. In the preferred embodiment, this adjustment is equal to 3 dB. However, other options ASU is further used to measure changes in power of the received signal 1605. In the preferred embodiment, automatic gain control detects changes in the power of the if signal. It is obvious that the measurement of changes in the received signal strength can also be performed on the RF or in the frequency band of the modulating signals of the receiver.If the change in signal power of approximately 3 dB, mdcr signal greater than the minimum level of noise, and intermodulation components that can cause problems, no. In this case, no additional gain, but increasing the gain will improve the receiver sensitivity. Changes in the power of the if signal of the order of (30,5) dB equals 3 dB.If changes in the power of 1610 the if signal is less than 3 dB, mdcr signal is less than the minimum level of noise or intermodulation components that can cause problems are not present. In this case, ANR see only small mdcr signals and noise. Therefore, it is necessary to increase gain 1615 in the circuit of the receiver and thus to improve the sensitivity of the receiver. If changes in the power of the if signal are more than 3 dB intermodulation components create a significant problem and needed updat is by 3 dB, intermodulation components change by 9 dB, if there are large interference. In this case, the average gain may be slightly reduced (approximately 3 dB) up until the method according to the present invention is not determined that the intermodulation components decreased to an acceptable level.When checking low intensity intermodulation components, the method of the present invention can be used continuously. In a preferred embodiment, the intensity is ten times per second. In other embodiments, the implementation of this method is used once during the period of the cycle. In some other embodiments, the implementation of this method is used with a different frequency, for example upon detection of a significant error in a straight line.An alternative implementation of the method of the present invention shown in Fig. 17. It introduces the "delay" time. As in the embodiment shown in Fig.16, this alternative can be used to adjust the gain of any circuit disclosed above, using any of the described power detector LNA and controllers. Moreover, it should be noted that chemical to other types of amplifiers with a fixed or variable gain.The process begins at block 1702 when the LNA, i.e., when LNA amplifying the received RF signal. In block 1704, the decision is determined whether the received power is greater than the block threshold, as previously discussed with reference to Fig.1. If the received power exceeds the lockout threshold, then the process returns to block 1702.The process continues with the active LNA up until in block 1704, the decision is not determined that the received power is actually larger than the block threshold, then the process passes to block 1706 where LNA "locked", i.e., prevents it from amplifying the received RF signal for a predetermined period of time. This predefined period of time may be defined as the "delay" time, which is desirable to limit the frequency of switching on and off LNA. By adding time delays in receiving automatic control loop gain can be sustained.After expiration of a predefined period of time (i.e. time delay) in block 1706 again measured received power and this time is compared with a threshold release in block 1708 decision. In preferably 1704 decision, what creates the ambiguity. However, this condition is not required.If the received power is greater than the threshold unlock, it is still quite high and LNA remains locked up until the received power drops below the threshold unlock. When the received power falls below the threshold unlock, as determined in block 1708 decision, the process continues at block 1710 decision to determine whether significant intermodulation components. This definition is best done by incorporating in a short period of time LNA and measure the "shifts" (i.e., the magnitude of compensation ANR) in the receiving automatic control loops amplification. As was disclosed with reference to Fig.16, the presence of significant intermodulation components should cause a greater increase in power of received signals, than the presence of only the useful signals. This excessive increase in power of received signals must force receiving automatic control loop gain to provide amplifiers ANR large control signal.If, as determined by block 1710 decision, znachitelnye, where LNA is disabled during a predefined period of time. However, if there are no significant intermodulation components, the gain in the input stage can be improved to enhance the performance of the receiver by unlock LNA and return to the unit 1702.In conclusion, we note that the method in accordance with the present invention allows a mobile wireless communications devices to move near the antennas of various systems, increasing at this time, the resistance device radio to RF interference from different systems. Lowering the gain in the input stage of the receiving circuit of the receiver device Radiocommunication increases so that emissions from signals of other systems do not cause poor operation of the receiver and demodulator.The preceding description of the preferred alternative implementation of the subject invention provides the opportunity for professionals in the art to implement and use the present invention. Various modifications of the above embodiments which are obvious to specialists, and the General principles set forth in the present description can be applied to other variants of implementation without the need to solve izobretatel it is supposed for use in the widest spheres, consistent with disclosed here, the principles and new features.
1. The method of changing the gain of the receiving circuit having an amplifier with fixed gain, comprising the steps of receiving the signal, the gain of the specified signal to the specified amplifier with fixed gain, measure the power of the amplified signal of the specified enhanced signal, the comparison indicated measured power amplified signal with the first threshold, preventing in the specified amplifier with fixed gain amplification of the specified received signal during the first predetermined time period if the specified measured signal strength is greater than the first threshold, the power measurement of the non-amplified signal of the specified received signal after the expiration of the first predetermined time period, the comparison indicated measured power of the non-amplified signal with a second threshold, re-amplification of the specified received signal specified by the amplifier during the second predetermined time period, measuring the power of re-amplified signal of the specified re-amplified signal, the difference between the specified yasunaga stage of amplification, if the measured power of the non-amplified signal is less than the second threshold, and specified a certain difference is less than a predefined value.2. The method according to p. 1, characterized in that it further comprises the step of preventing at the specified amplifier with fixed gain amplification of the specified received signal within a specified first predetermined time period if the specified power consumption measured non-amplified signal is not smaller than the second threshold, or specified a certain difference is not less than the specified pre-defined value.3. The method according to p. 2, wherein said first threshold is greater than the second threshold.
FIELD: communication systems.
SUBSTANCE: one of methods is method for providing linear adjustment of level of output power of transmitter, containing device with multiple discontinuous setting values of amplification coefficient, and device with smooth adjustment of setting value of amplification coefficient, including steps for determining amplitude transfer function of transmitter for each said set of discontinuous setting values, forming of compensation table for amplification coefficient, receiving said setting values, reading compensated setting value of amplification coefficient from compensation table, adjustment of amplification coefficient.
EFFECT: higher efficiency, broader functional capabilities, lower costs, higher reliability, higher durability.
9 cl, 27 dwg