SU1601769A1 - Device for searching for noise-like signals - Google Patents

Abstract

The invention relates to a technique for receiving and processing noise-like signals (PSS) and can be used to search for and establish synchronism in broadband communication systems. The purpose of the invention is to reduce the average signal search time. The device for searching noise-like signals contains a correlator 1, a generator 2 of a reference signal, And 3, 4 elements, a generator of 5 clock pulses, a driver of 6 pulses, counters 7.8 and 9, a decoder 10, a trigger 11, a memory block 12, a comparison block 13 and the elements OR 14 and 15. After establishing the initial zero state, the correlator 1 from generator 2 is supplied with a pseudo-random sequence. In counter 9, the number of matching pulses is analyzed. At the same time, an analysis interval is estimated in counters 7 and 8. When the duration of the latter exceeds a predetermined threshold, the threshold level changes in accordance with the values recorded in memory 12 at the addresses generated by counter 8. The number read from memory 12 is compared in comparison block 13 with the number accumulated in counter 9 If they match, the phase of the reference signal changes by eliminating one clock pulse. At the same time, the average analysis time for each position is reduced with the likelihood of a false alarm and the correct detection of a signal is not worse than the specified ones. 1 il.

Description

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pulses, counters 7, 8 and 9, decoder 10, trigger 11, memory block 12, comparison block 13, and OR elements 14 and 15. After establishing the initial zero state, the correlator 1 from generator 2 is fed to a pseudo-random sequence. In counter 9, the number of matching pulses is analyzed. At the same time, an analysis interval is estimated in counters 7 and 8. When the duration of the latter exceeds a predetermined threshold, the threshold level changes in accordance with the values recorded in memory 12 at the addresses generated by counter 8. The number read from memory 12 is compared in comparison block 13 with the number accumulated in counter 9 If they match, the phase of the reference signal changes by eliminating one clock pulse. At the same time, the average analysis time for each position is reduced with the likelihood of a false alarm and the correct detection of a signal is not worse than the specified ones. 1 il.

The invention relates to a technique for receiving and processing noise-like signals and can be used in search and synchronization schemes for received pseudo-random signals.

The purpose of the invention is to reduce the average signal search time.

The drawing shows a structural electrical circuit of a noise-like signal searching device.

The device contains a correlator 1, a generator 2 of the reference Signal, the first 3 and second 4 elements And, the generator 5 clock pulses, shaper 6 pulses, the first 7, second | 5th and third 9 counters, decoder 10, trigger 11, block 12 memory , - comparison unit 13, first 14 and second 15 elements OR.

The device works as follows.

Before operation, the device at the installation input is reset, i.e. the initial phase of the reference signal generator is set, counters 7 and 8 of the analysis interval are set to zero through the OR 14 element, the trigger threshold is set to O, the detection threshold is set to the threshold counter 9.

After the termination of the set signal at the output of the imager 6, a signal is generated allowing the clock to pass from the generator of 5 clock pulses through the AND element to the generator 2 of the reference signal. The periodic input information sequence O and 1 is sent to the information input of the correlator. And the other signal from the generator with the same period receives the reference signal from oscillator 2. 9 threshold. At the same time counting the number

cycles from the beginning of the analysis interval in series-connected meters 7 and 8 of the analysis interval. Prior to overflow of the counter 7, the output of the counter 8 is formed

a constant zero address by which from the memory unit 12 a number is chosen, at least one greater than the threshold level value, recorded when the threshold is set at the counter 9.

After the overflow of the counter 7, the signal from its output resolves the counting on the counter 8, which forms the address for sampling the threshold value from the memory block 12. If the number is equal to him in counter 9, a situation is realized in which the probability of the absence of a signal at the position under study is equal to or greater than D, respectively, and the probability of missing a signal is less than or equal to the specified one. The equality signal from the comparison block 13, having passed through the elements OR 15, AND 4 and OR 14. confirms the initial state of trigger 11, writes the initial threshold to the counter 9 of the threshold, resets counters 7 and 8. In addition, the pulse shaper 6 is blocked, the output signal which prevents the reference signal generator 2 from passing one clock pulse from generator 5, whereby the reference signal generator 2 begins to form a reference signal in a new phase, and the described process of searching for noise-like signals repeats.

Possible transition to the study of the new position on the overflow of the counter 8.

In the case when the phase of the reference signal coincides with the phase of the received signal, there is an intensive decrease in the number in the counter 9 threshold, it remains all the time less than the threshold value received

to the second input of the comparator unit 13 from the memory unit 12. When the counter 9 is zeroed, the decoder will generate a signal that triggers trigger 11. The signal at the forward output of trigger 11 indicates synchronism. At the same time, the low level signal from the inverted output of the trigger 11 prohibits the passage of the overflow signal of the counter 8 through the AND 4 element, fixing the phase of the reference signal.

Claims (1)

Invention Formula The device for searching noise-like signals contains a correlator whose first input is the device input, and the second is connected to the output of the reference signal generator, the first input of which is set, and the second control input is connected to the output of the first And element, the first input which is connected to the output of the clock pulse generator, the output of which is also connected to the input of the first counter and the clock input of the relay, as well as the comparison unit and the trigger, the inverse output of which is connected to the first input of the second element And, and the direct output is the output of the device, characterized in that, in order to reduce the average signal search time, the first OR element, the second and third counters, the pulse shaper, the decoder, the memory unit and the second OR element are added, and The first input of the first element OR is connected to the first input of the generator of the reference signals, and the second to the output of the second element AND, and the output to the control inputs of the first counter, second counter, pulse generator, the setup input of the trigger and the control input t of the counter, whose counting input is connected to the output of the correlator, and the output is connected to the input of the decoder, the output of which is connected to the counting input of the trigger, and the input of the decoder is connected to the first input of the comparator, the output of which is connected to the first input of the second OR element, the second input connected to the overflow output of the second counter, the first input of the resolution resolution of which is connected to the overflow output of the first counter, and the counting input to the output of the clock generator, the second output of the second counter is connected address input of the memory unit, whose output is connected to the second input of the comparing unit.