SU1566495A1 - Device for reception of sounding signal - Google Patents

Abstract

This invention relates to radio. The purpose of the invention is to improve the noise immunity with respect to the frequency shifts of the carrier wave. The device contains a delay unit 1, a key 2, an amplitude detector 3, high-pass filters 4 and 12, comb filters 5 and 13, rectifiers 6 and 14, low-pass filters 7 and 15, comparators 8 and 16, element OR 9, block 10 filtering, frequency converter 11 - voltage and counter 17. The input signal containing periodically repeating sections - communication channel responses to probe pulses transmitted between packets of information signals, passes after a delay in block 1 through switch 2 to the device output at those times time when the input signal is Makes a channel response to the probe signal. In this case, the pulses at the control input of the key 2 are formed from the input signal in such a way that their position in time does not depend on the absolute value of the carrier frequency, as a result of which the noise immunity of the device is increased. 1 hp f-ly, 4 ill.

Description

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The invention relates to radio and can be used in receivers of discrete messages.

The purpose of the invention is to improve the noise immunity with respect to the frequency shifts of the carrier wave.

Fig. 1 shows the electrical circuit of the proposed device; in fig. 2 is a structural .Q electrical circuit of the filtering unit} in FIGS. 3 and 4 are timing diagrams,

The device for receiving the probing signal contains a block 1 delay, a key 2, an amplitude detector 3, the first |. high pass filter 4, first comb filter 5, first rectifier 6, first low pass filter 7, first comparator 8, element OR 9, filtering unit 10, frequency-voltage converter 11, second high pass filter 12, second comb filter 13 , the second rectifier 14, the second low-pass filter 15, the second comparator 16 and the counter 17.

The filtering unit contains a front edge selector 18, a first phase discriminator 19, a first averager 20 phase fluctuations, a first controlled frequency divider 21, a logic driver 22 pulses, a back edge separator 23, a second phase discriminator 24, a second averager 25 phase fluctuations, a second controlled frequency divider 26, generator 27, first block 28 And elements, synchronization indicator 29, second And element block 30 and frequency divider 31,

The device works as follows.

An input signal containing periodically repeating (along the complex envelope) sections — channel responses to probe pulses transmitted between packets of information signals (FIG. 3 a, 6J) after a delay in block 1, the delay passes through key 2 at times when The input signal is the response of the communication channel to the probing signal. The pulses at the control second input of key 2 are formed from the input signal so that their position in time does not depend on the absolute value of the carrier frequency.

The source of information about the temporal position of the communication channel response to the probe signal is oscillator 30

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processes that reflect the laws of variation of the amplitude and instantaneous frequency of the input signal (Fig. 3c, d). From FIG. 3c, d it follows that both the amplitude, both the time function and the instantaneous frequency have periodically repeating sections, This is explained by the fact that if a signal with a constant envelope arrives at the input of the communication channel (Fig. 3a), information in which it is embedded in the modulation of a non-energy parameter, for example, the initial phase and frequency, then at the output of the communication channel it turns out to be modulated in amplitude due to transients in the linear circuits of the channel-forming equipment, as well as in the signal propagation medium (due to p, multipath) Periodicity sounding signal transmission by changing, e.g., the initial input phase leads to the fact that the periodic law component is present varying signal amplitude at the channel output. The same can be said about the law of variation of the instantaneous frequency. The periodic components in the laws of changes in amplitude and instantaneous frequency coincide in time with the response of the communication channel to the sounding signal, since they are generated by it.

Oscillatory processes corresponding to the laws of amplitude and instantaneous frequency variation are measured using an amplitude detector 3 and the first high-pass filter 4, and also the 4-frequency converter 4 - voltage and the second high-pass filter 12, respectively (Fig. 4 a, d), Through the first 5 and the second 13 comb filters the periodic components run without attenuation, because the peaks of their amplitude-frequency characteristics coincide with the frequencies of the discrete components of the spectrum of the periodic components, where F, is the frequency of the probes ani channel; k is the harmonic number. Random processes generated by modulation, information signals in work packets, as well as channel interference, are significantly weakened (Fig. 4, b, e). Thus, the first 5 and second 13 comb filters select periodic processes that coincide in time with the response of the communication channel to the probe signal, from which, using sequentially

the first (second) dual-periodical rectifier 6 (14) - (fig. 4, A), the first (second) low-pass filter 7 (15) of the first (second) comparators 8 (16) are formed; periodic pulse sequences are formed (Fig. 4g, g), the levels of which correspond to logical 1 during the channel response and logical O in pauses. These pulse sequences are combined in the logical element OR 9 and, after averaging in filtering unit 10, are sent to the control second input of key 2 with the help of which temporary selection is carried out and channel response to the probe signal (its reception).

In filtering unit 10, the front and rear edges of the input periodic pulse signal are separately averaged over a temporary position. Fronts are formed by the front 18 and rear 23 emitters of the pulse. Their time position is averaged using phase-locked loop systems with indirect control of the frequency and phase of the frequency-stabilized generator 27 formed by the first (second) phase discriminator 19 (24), the first (second) averager 20 (25), the first ( second) controlled pulse frequency divider 21 (26). At the output of the logic driver 22 pulses, controlled by averaged over the temporal position of the front and rear edges, a periodic sequence is formed corresponding to the time and duration of the communication channel response to the sounding signal. From the second input of the filtering unit 10 from the frequency-controlled generator 27 through the first controlled divider 21 of the pulse frequency or through the divider 31 of the pulse frequency, as well as the second block of 30 elements And the input of the counter 17 receives control pulses or synchromesh ated with the arrival of conductive signal or not synchronized. The command to switch the second 30 and first 28 blocks of elements And is produced by the circuit formed by the synchronism indicator 29, If the mismatch in the temporary position between the second pulse sequence (not averaged over the fronts) and

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the average (from the output of the logic driver 22 of them of guls) is greater than a certain threshold value, then in order to reduce the transient time when entering the connection to the second output of the filtering unit 10, the control pulses are not synchronized with the input signal, and the first output does not averaged over the edges of the input control pulses of key 2, if the phase-locked loop systems are in phase with the input signal, the signal from the output of the synchronization indicator 29 switches the first 28 and second 30 blocks The elements And are in the transmission mode on the first output of the averaged On the fronts of the control key impulses 2, and on the second output - the pulses of the counter 17 synchronized with the input signal.

Claims (1)

Invention Formula 1, A probing signal receiving device containing a key, first and second high-pass filters, first and second low-pass filters, a counter and first and second comparators, which is different from the fact that, in order to improve the noise immunity with respect to the frequency shifts of the carrier oscillations, an OR element, a filtering unit, two rectifiers, two comb filters, an amplitude detector, a frequency-voltage converter and a delay unit, whose input is connected to the input of the frequency-voltage converter and to the amplitude input tector, the output of which is connected to the first input of the first comb filter through the first high-pass filter, the output of which through the first straightener connected in series, the first low-pass filter and the first comparator connected to the first input of the OR element, the output of which is connected to the input of the filtering unit, the first output which is connected to the input of the counter, the outputs of which are connected to the second inputs of the first comb filter and the second inputs of the second comb filter, the output of which is through The second driver, the second low-pass filter and the second comparator are connected to the second input of the OR element, the output of the frequency-voltage converter through the second high-pass filter connected to the first input of the second comb filter, and the output of the delay block is connected to the first input key, the second input of which is connected to the second output of the filtering unit. 2, The device according to claim 1, of tl and 10 20 that the filtering block contains two blocks of AND elements, a frequency divider, a logical pulse shaper, a generator, a synchronism indicator, two controllable de- (, frequency generator, two phase fluctuation averagers, two phase discriminators, a trailing edge of the pulse and a front edge of the pulse front, the output of which is connected to the first input of the first phase discriminator, the output of which is connected to the first input of the first controlled frequency divider through the first averager of phase fluctuations, turn 25 is connected to the second input of the first phase discriminator and a first input of a logic pulse shaper whose output is connected to the first input of the indicator and JQ synchronism with the first input element of the first block 0 , 5 Q cops And, the second input of which is connected to the second input of the synchronization indicator i, to the input of the leading edge selector and to the input of the leading edge selector, the output of which is connected to the first input of the second phase discriminator, the output of which is connected to the first input of the second controlled through the second averager of phase fluctuations frequency divider, the second input of which is connected to the second input of the first controlled frequency divider, to the generator output and to the input of a frequency divider, the output of which is connected to the second input of the second the block of elements And, the first output of which is connected to the second output of the first controlled frequency divider, the output of the synchronization indicator is connected to the third inputs of the first and second blocks of elements And, the output of the second controlled frequency divider is connected to the second input of the second phase discriminator and to the second input of the logic driver pulses, the second input of the synchronization indicator being the input of the filtering unit, the first and second outputs of which are the outputs of the first and second blocks, respectively. AND. FIG. 2 l H / h 4- 4- v- 4- 4x  -. -N, 4, .. " / , -h / h  h- / l / h / iG hh h / y Fig.Z