RU2571731C2 - Method of transmitting telemetric and video information with radio link frequency-time multiplexing and analogue-digital method for frequency (phase) modulation of carrier frequency and device therefor - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to transmission of telemetric and video information. The method and device include generating, for every information, a synchronous stream, in each of which channel time-division is performed at clock frequency with a duty ratio Q=2, wherein each stream is separated from the stream adjacent on carrier frequency by a frequency interval equal to F_cyc×n, and is offset in time by a half cycle. A high-frequency video signal is subjected to time sampling, while reducing resolution and frame frequency. Packed streams of telemetric and video information are transmitted via a radio link.

EFFECT: enabling transmission of a video image of processes in the frequency band of the used radio link.

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Description

The invention relates to radio telemetry systems, in particular to systems for transmitting telemetric information in the space industry.

A known method of transmitting telemetric information [1], based on the formation of signals proportional to the change in physical values, comparing these signals with a calibration scale, forming differential signals and transmitting information to a receiving station.

The disadvantage of this method is the limited number of channels with the used frequency band and small functionality when transmitting information about the processes.

A known method of receiving radio signals emitted by the principle of a time-frequency matrix, in particular, for signals with bitwise frequency hopping and random binary frequency modulation, when code symbols 0 and 1 are independently selected in the entire frequency band Δf _total , i.e. when M symbols are transmitted at the same time at different frequencies, a multichannel receiver is used, the number of receivers in which is determined by the number M of frequency positions of the radio signal [2].

However, the implementation of such a method and device in telemetry would require the use of an unreasonably large frequency band on the air and the use of M receive paths, which is difficult and expensive. It is also impossible to transmit video information about the processes at a remote observation object.

.The closest in technical essence to the claimed method of transmitting telemetric and video information and a device for its implementation is a method of transmitting telemetric information with time-frequency compression of the radio channel and the analog-digital method of modulating the carrier frequency and a device for its implementation [3], in which the information is transmitted according to N (where N = 2, 4, 8, ...) synchronous flows, in each of which at the clock frequency F _, channel separation in time _is performed with a duty cycle of Q = 2; in this case, each stream is separated from the adjacent carrier frequency by a frequency interval equal to Δfp = F _so × n (where n = 5, 6, 7, ...), and is shifted in time by half a clock cycle $$\tau =\frac{\mathrm{one}}{2F_{t\mathrm{but}\mathrm{to}}}$$

.

A device that implements this method includes: a clock generator; frequency divider; marker pulse shaper; phase detector; frequency modulator; controlled generator; amplifier; reference carrier frequency generator; switches adder; shaper frequency "stand".

The disadvantage of this technical solution is that it does not allow transmitting a video image in the frequency band of the used radio channel without significantly expanding the number of channels and complicating the equipment.

The expected technical result of the method and device for transmitting telemetric and video information with time-frequency compression of the radio channel is to ensure the transmission of telemetric and video information in the frequency band of the used radio channel without increasing the number of channels.

, высокочастотный сигнал видеоинформации повергают временной дискретизации, снижая разрешение и частоту кадров, генерируют маркерные видеоимпульсы, затем из полученных сигналов формируют один из синхронных потоков, который уплотняют с потоком телеметрической информации и передают по радиоканалу.To do this, in the method of transmitting telemetric and video information with time-frequency compression of the radio channel and the analog-to-digital method of frequency (phase) modulation of the carrier frequency N (where N = 2, 4, 8 ...) with synchronous video streams, each of which at the clock frequency F _so the channels are separated in time with a duty cycle of Q = 2, with each stream spaced from the neighboring carrier frequency in the frequency interval Δfp = F _so × n (where n = 5, 6, 7 ...) and shifted in time by half a clock cycle

, the high-frequency video information signal is subjected to temporal sampling, decreasing the resolution and frame rate, marker video pulses are generated, then one of the synchronous streams is formed from the received signals, which are compressed with the telemetric information stream and transmitted over the air.

In addition, to a device for implementing the method, comprising a series-connected clock generator, a frequency divider, a marker pulse shaper, a phase detector, a frequency modulator, a controlled generator and a power amplifier, a reference carrier frequency generator, the output of which is connected to the second input of the phase detector, to the third input of which is connected to the second output of the controlled generator, the first switch, the input of which is connected to the second output of the clock, an adder connected between at the output of the first switch and the second input of the frequency modulator, the second switch connected between the third output of the clock and the second input of the adder, the frequency shaper, connected between the third output of the clock and the third input of the frequency modulator, a series-connected video camera, selector video sync pulses and a video marker former connected to the second input of the second switch, a video information sampler, connected between they output clock frequency generator and the third input of the second switch, a video camera output is connected to a second input of video sampler, a third input coupled to a first input of the videomarkera, a second input coupled to a first input of the second switch.

The joint functioning of the telemetry and video information flows will be considered using the example of a two-stream (N = 2) radio channel.

In FIG. 1 shows the signal structure of a single-stream telemetry system used to form a two-stream signal, including:

a) signals at the input of the frequency modulator of a single-threaded transmitter;

b) pulses blocking the output stage of the transmitter and providing the emission of signals into the air with a duty cycle of Q = 2;

c) radio pulses at the output of the transmitter.

In FIG. 2 shows the structure of the signals of the second stream with sampled video information used to form a two-stream signal, including:

a) video information signals at the input of the frequency modulator of a single-threaded transmitter;

b) pulses blocking the output stage of the transmitter and providing the emission of signals into the air with a duty cycle of Q = 2;

c) radio pulses at the output of the transmitter.

In FIG. 3 shows the structure of a dual-stream radio signal.

In FIG. 4 shows a block diagram of a device for forming a joint stream of telemetric and video information.

In a single-threaded transmitter, the measurement information received from the sensors is transmitted by the method of frequency or phase modulation of the carrier frequency in analog or digital form (AIM / CMM - FM (FM) modulation), where AIM is pulse-amplitude modulation, KIM is pulse-code modulation. When switching to a two-stream radio line (the modulation method of the carrier of each stream remains the same), in the pauses of the single-stream fп1 radio line (Fig. 3), a second stream fп2 is operating at the same clock frequency F _so that the first stream. To ensure the reception of these streams without interference, the carrier frequencies of both streams are distributed over the frequency interval Δfp = F _so × n (where n = 5, 6, 7 ... is an integer determined experimentally from the minimum allowable interference between the streams at the minimum frequency separation).

The first stream consists of sequentially switched signals from measuring sensors and service signals (marker pulse, calibration). To coordinate the band of the radio channel, the channel capacity of the transmitter-receiver and hardware capabilities, the signals from the video camera are subjected to temporary sampling, which consists in reducing the frame rate and image resolution, form a marker video pulse. Then, a second stream is formed from the signals obtained after sampling and the marker video pulse.

A device for implementing the method comprises a clock generator (1), a frequency divider (2), a marker pulse shaper (3), a phase detector (4), a frequency modulator (5), a controlled generator (6), a power amplifier (7), a reference carrier frequency generator (8), first switch (9), adder (10), second switch (11), frequency “stand” former (12), video camera (13), video sync selector (14), video marker former (15), video information sampler (16).

The device operates as follows: the switch (9) collects measurement information from the sensors, the switch (11) receives video information from the video camera (13). Both switches (9, 11) are synchronized from one clock generator (1) operating at a frequency F _{like that} . High-frequency and highly informative video information is supplied to the video-sync pulse selector (14), in which synchronizing pulses are allocated, and to the video information sampler (16). Video information using F _and timing pulses optimized for a valid informative (J) radio channel, according to the relationship J = P × H × G × K,

where P is the number of pixels in the line of the video frame,

H is the number of lines in the video frame,

G is the number of frames

K is the number of information channels in the stream.

To bind to the beginning of the video information, the video marker shaper (15) creates a video marker signal. Further information through the adder (10) is fed to the input of the frequency modulator (5). At the other input of the frequency modulator (5), the output of the frequency “stand” former (12) receives a control two-level voltage of 2 × F in _{such a} way that provides jump-like changes in the frequency of the frequency modulator (5) and a “spread” in the frequency of flows 1 and 2 to the frequency the spacing Δfp = F _so × n, while the frequency jump occurs without breaking the phase of the carrier wave.

The phase locked loop (PLL) - blocks (4), (5), (6), (7) - provides adjustment of the carrier frequency of the stream according to the level of the marker pulse, the value of which corresponds to the middle of the measuring scale of the stream and the nominal value of the carrier frequency of the emitted signal. The PLL operation ensures that the carrier frequencies of flows 1, 2 are linked to each other and to the frequency of the reference oscillator (8).

Sources of invention

1. RF patent No. 2313816, 2004.

2. A.S. No. 938417, 1982.

3. RF patent No. 2236754. 2004.

Claims (2)

1. A method of transmitting information with time-frequency multiplexing of a radio channel and an analog-to-digital method of modulating the carrier frequency N (where N = 2, 4, 8 ...) with synchronous video streams, in each of which at the clock frequency F channel separation in time _is performed with a duty cycle Q = 2, with each stream spaced from the neighboring carrier frequency in the frequency interval Δfp = F _so × n (where n = 5, 6, 7 ...) and is shifted in time by half a clock cycle $$\tau =\frac{\mathrm{one}}{2F_{t\mathrm{but}\mathrm{to}}}$$

characterized in that the high-frequency video information signal is temporarily sampled using a video information sampler and dedicated video clock pulses for generating video information using a clock frequency generator F _so as to optimize the video information for the permissible information content (J) of the radio channel so that the relation J = P × H × G × K, where P is the number of pixels in the line of the video frame, H is the number of lines in the video frame, G is the number of frames, K is the number of information channels in the stream; marker video pulses are generated, then one of the synchronous streams is formed from the received signals, which are compressed with the telemetric information stream and transmitted over the air. 2. A device for implementing the method according to claim 1, comprising serially connected clock generator (1), frequency divider (2), marker pulse shaper (3), phase detector (4), frequency modulator (5), controlled oscillator (6 ) and a power amplifier (7), a reference carrier frequency generator (8), the output of which is connected to the second input of the phase detector (4), to the third input of which the second output of the controlled generator (6) is connected, the first switch (9), the input of which is connected to the second output of the clock (1), sums an atator (10) connected between the output of the first switch (9) and the second input of the frequency modulator (5), a second switch (11) connected between the third output of the clock generator (1) and the second input of the adder (10), the frequency shaper "(12), connected between the third output of the clock generator (1) and the third input of the frequency modulator (5), characterized in that a series-connected video camera (13), a video sync selector (14) and a video marker former (15) are inserted into it connected by an output to the second input to the second switch (11), a video information sampler (16), connected between the third output of the clock generator (1) and the third input of the second switch (11), the output of the video camera (13) is connected to the second input of the video information sampler (16), the third input of which connected to the first input of the video marker former (15), the second input of which is connected to the first input of the second switch (11).

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