The way of reception, demodulation and processing of signals from satellite and microwave links

 

The invention relates to the field of radio and digital technology. The technical result consists in increasing the efficiency at short-term reduction of the signal-to-noise ratio at the input of the device below a threshold level, leading to synchronization failure. The inventive signal with high signal to noise and providing frame synchronization is processed in real-time by the hardware, and when it crashes synchronization digital signal after demodulation is recorded on a hard magnetic disk of the personal computer and then processed in petrolina time software methods and results of processing the corrected information hardware. 2 Il.

The method relates to the field of radio engineering and digital technology and can be used at the reception, demodulation, softening and kaylamichaely different signals with a temporary seal.

The need to transfer large amounts of information has led to the creation of an extensive satellite and radio-relay communication lines with complex transformations of digital streams on the transmitting side and the various modulation types: CCITT recommendations 232 G, G, 733, G, 741, G746, G747, G751, G752, G754 and d and are usually developed their own special equipment for reception, demodulating and processing in a consolidated way in which: - the signal is received and converted into an intermediate frequency signal demodulator is converted into a digital stream; - from a digital stream selectrow the synchronization signals in the frequency interval of the digital stream; - count the number of clock pulses since the selection of the clock; - the results of the counting form the gates for each component of the digital stream (service bits, the bits of information flows, team management, staffing, bits staffing); - emit heartbeats each of the components of the digital stream; - clock signals selected parts selectrow information from total digital stream.

The disadvantage of this method is its determinism for each type of seal and the complexity of hardware implementation.

By this method built domestic equipment for signals PCM-30, PCM-120, PCM 480, PCM 1920 and foreign equipment.

In [3] proposed a method that adapt the apparatus to different types of seals.

According to this method, as similar: - the signal is received and converted into an intermediate frequency signal demodulator - Aly synchronization in the frequency interval of the digital stream signal personnel, supernatrual or sverchkova synchronization);
- synthesize the model of the digital stream (signal);
- put the model signal in memory;
- the synchronization signal synchronous with the digital stream read model signal from the random access memory (RAM);
- generate clock signals of the respective parts of the digital stream;
- selected clock signals selectrow information part components of the digital stream.

The disadvantage of this method is low efficiency when reducing for some reason, the signal-to-noise ratio at the input of the device below a threshold level, which leads usually to a breakdown of the synchronization system and the loss of information.

The aim of the invention is to increase the efficiency at short-term reduction of the signal-to-noise ratio at the input of the device below a threshold level, leading to synchronization failure.

To achieve this goal it is proposed a method in which the signal is received (converted into intermediate frequency (if), demodulator (converted into a digital stream), from a digital stream selectrow the synchronization signals in the frequency interval of the digital stream signal personnel, supernatrual and beyond memory and synchronization signal synchronous with the digital stream read model signal from the memory and generate the clock signal components of the digital signal, which selectrow information part components of the digital stream.

According to the invention continuously monitor the presence of synchronization (for personnel, superquadras, sverhmudry), and in violation of the synchronization signal after demodulation record on a hard magnetic disk of the computer. Then on optimal algorithms software methods in petrolina time they process the signal (define signal timing and with reference to them demultiplexer stored in the memory of the digital stream). According to the results of processing correct information received by the hardware, thus avoiding the loss of information due to the synchronization failure caused by interference or reduction for any reason the signal/noise ratio, i.e. the processing of received signals in petrolina time that allows the use of optimal algorithms synchronization, decoding and demuxing, which, although they take more time than the operation of equipment in real time, but you can handle signals with a low signal-to-noise (error).

The task of processing signals at low signal to noise (greater lending and technical methods leads to a significant complication of all devices. In particular in [1, C. 101], the circuit-technical solution adaptive receiver clock, which is significantly harder than non-adaptive scheme of the receiver. A similar pattern is observed for other adaptive devices tract reception, demodulation and processing of digital streams.

Such a decision are not described in literature, so the method meets the criteria of novelty and inventive step.

In Fig. 1 shows a structural block diagram of the device for the proposed method.

In Fig.2 shows the structural diagram of the device high-speed input.

The proposed method performs the following sequence of operations:
- the signal is received (converted into intermediate frequency (if);
signal demodulator (convert the signal into a digital stream accompanied clock frequency);
- from a digital stream selectrow the synchronization signals in the frequency interval of the digital stream signal personnel, supernatrual or sverchkova synchronization);
- synthesize a model of the processed signal;
- put the model signal in memory;
- the synchronization signal synchronous with the digital stream read model signal from the RAM;
- form tacticion part of the components of the digital stream;
- continuously monitor the availability of personnel, supernatrual and sverchkova synchronization;
- in case of violation of sync (because of the increasing number of errors in a digital signal) the signal after demodulation is converted into a parallel code and write it to a hard magnetic disk of a PC;
- known algorithms using a personal computer to produce detailed processing of the recorded digital stream in petrolina time scale and allocate information of the component parts of the total input digital stream;
- according to the results of processing correct information hardware.

The structure of the device that implements the proposed method (Fig.1) are connected in series radio receiver 1, desmodoridae device 2, the clock selector 3, RAM schemes writing and reading 4, the regenerator 5 cycles, the regenerator information 6, and the PC signal model 7 and the delay blocks 8, 9. Thus the outputs of the demodulator 2 is connected to the inputs of the high-speed input device 10, entered in the PC 7, the output of synchronizer 3, indicating the synchronization fails, connected to the input of the PC 7, the inputs of the delay blocks 8 and 9 are connected to a clock and data outputs of the demodulator 2, the output element CU, and outputs - the outputs of the regenerator 6, and when the synchronization failure - outputs PC 7.

The device operates as follows.

The input signal at a high frequency (for example, in the range of 500-2000 MHz) is fed to the input RPU 1, where the signal is filtered and converted into an intermediate frequency (e.g., 70 MHz). Further, the signal demodulator (converted into digital form) in the demodulator 2. The signals after demodulation accompanied by a clock frequency of an input clock selector 3. The selected clock is started to read the RAM 4, in which pre-recorded model of the signal synthesized in the PC 7. Next, the clock signal components flows recovered in the regenerator 5-compensated delay element 8 and these signals strobert the information coming from the demodulator 2 with compensation of the delay element 9. Resulting at the output of the regenerator 6 is formed information flows components of the total digital stream (service bits, bits command staffing, bits of staffing, the bits of the alarm bits combine component flows, and so on).

If it fails for any reason, the synchronization unit 3 issues a command to the PC 7, and allows the recording of digital stream after demodulate device, and the signal recorded in the PC 7 is postreading time programmatically. According to the results of signal processing using the PC 7 adjusting the output device.

The memory capacity of the HDD modern PC reaches ~40 GB. Velocity information after the demodulator 2 is a maximum of 150 Mbps, which, given a 3-bit soft decisions (for decoding procedure Viterbi soft decision) will be ~450 MB/s or ~56 MB/s

If the memory capacity of 40 GB recording time of the signal will be 40000 GB: 56 MB=700 ~11 minutes

To maintain a record high speed digital stream from the demodulator 2 on the PC 7 PC component entered the high-speed input device (UVV) 10 made on the card inserted into one of the ports of the PC 7 (Fig.2).

Part UVV are connected in series Converter in parallel code 11, the PCI bridge 12, a controller RAID HDD 13 and 14, the PCI bridge 12 and the RAID controller 13 is connected to the PCI bus of the PC 7.

UVV is as follows.

Digital stream from the demodulator 2 in the form of single-bit hard decision or a 3-bit soft decisions supplied to the inverter in parallel code where it is converted to 16 - or 32 - bit code. Gave the synchronization. After establishing synchronization PC 7 passes in a mode of processing of the recorded signal, extracting it from the HDD 14 via the RAID controller 13. According to the results of processing the corrected information hardware. The use of the method obtained the following results:
- provides recording digital signals the breakdown of synchronization;
- provides processing and allocation information of machine methods recorded digital stream and restoring information in the intervals where the hardware does not provide signal processing.

Currently, a breadboard model of a high speed input, conducted testing, and work was also carried out by software processing, digital streams in petrolina time. The positive results.

Sources of information
1. L. S. Levin, M. A. Plotkin. Digital transmission systems. - M.: Radio and communication, 1996.

2. C. L. Banquet, C. M. Dorofeev. Digital techniques in satellite communications. - M. : Radio and communication, 1998.

3. Patent 2122291 from 20.11.1998.


Claims

The way of reception, demodulation and processing of signals from satellite and radio-relay communication lines, wherein the signal is received, convert the personnel, supernatrual, sverchkova synchronization in the frequency interval of the digital stream, synthesize the model of the digital stream, put the model of the digital stream into memory, the synchronization signal synchronous with the digital stream read pre-recorded digital stream from an online storage device, generate the clock signal components of the digital stream, the selected clock signals selectrow information part components of the digital stream, characterized in that constantly monitors the availability of personnel, supernatrual and sverchkova synchronization and in case of violation of the synchronization signal after demodulation is converted into a parallel code and write it to a hard magnetic disk of the personal computers, then the recorded digital stream handle programmatically in petrolina time and produce informational components of the total input digital stream.

 

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