SU1653170A1 - Device for noise-like signal searching - Google Patents

Abstract

The invention relates to telecommunications and can be used in broadband radio communication systems. The aim of the invention is to reduce the search time for noise-like signals. The device for searching noise-like signals contains a mixer 1, a wideband amplifier 2, a demodulator 3, a narrowband amplifier 4, a low-pass filter detector 5, a controlled local oscillator 6, a phase discriminator 7, a correction amplifier 8, a controlled clock, a generator 9, quadrature correlator 10, threshold unit 11, shift register 12, pseudo-random sequence generator 13, pulse counting unit 14, decoder 15, shaper of 16 time interval signals, switch 17, inverter 18, elements 19–22. At the beginning of the search GUSTs operates in relation to small relative interference / signal and quickly with time analyzing the first stage of the first search cycle, scans the entire area of uncertainty signal delay equal to N elements. If the signal is detected at the first stage of the first search cycle in any cell of the uncertainty area, then the verification of the detection is performed with a gradual increase in the analysis time by moving to the subsequent stages and returning to the same stage of the first cycle with false detection. If, after analyzing all the cells in the first search cycle, all detections turn out to be false and a signal is missing, the parameters of the subsequent cycle stages (their analysis time) will be set optimal for a higher calculated interference / signal ratio. In the event that the K-th search cycle is reached, the optimal parameters of the stages of which are designed for maximum interference, these parameters on the subsequent search cycles remain unchanged, 1 sludgeon (L & a &

Description

The invention relates to telecommunications and can be used in broadband radio communication systems.

The purpose of the invention is to reduce the search time for noise-like signals.

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

The device for searching noise-like signals contains a mixer 1, a wideband amplifier 2, a demodulator

31

3, narrowband amplifier 4, 5 g detector low pass filter, controlled local oscillator 6, phase discriminator 7, correction amplifier 8, controlled clock generator 9, quadrature correlator 10, threshold unit 11, shift register 12, pseudo-random generator 13 sequences, counting unit 14 pulses, decoder 15, shaper 16 time interval signals, switch 17, Inverter 18, first, second, third and fourth elements AND 19 - 22.

The counting unit of 14 pulses contains a frequency divider 23 and a pulse counter 24.

The device search noise-like signals works as follows.

The input of the mixer 1, and through it the broadband amplifier 2, then the quadrature correlator 10 is affected by a mixture of interference and a received noise-like signal (PSS) with an unknown delay. The task of the search device for noise-like signals is to determine the PSS delay and the accuracy determined by signal uncertainty function. For this, the generator 13, which forms the elemental pseudo-random sequence, sends a copy of the signal to the quadrature correlator 10, which is tuned sequentially in time with a step где, where Fc is the width of the NPS bandwidth in the first stage of the first search cycle once per time T. integrating the processing of the result of the received signal in the quadrature correlator 10, since in this case, the output of the threshold block 11 contains a logic level O and impulses upayuschie a first input of the second AND gate 20 output from the switch 17 with a duration equal to the period of clock pulses TTH controlled oscillator 9, prohibiting passage through the third AND gate 21 one clock pulse at time interval T W

Register 12, in the absence of synchronism, is in the initial state, in which one is recorded in its first discharge, and in all other Impulses, it arrives. from the output of switch 17 through

. Q 5

0

5 Q Q 5

five

704

The first element, And 19, to the fault input of register 12, reliably holds the last in the initial state.

If at some point in the first stage of the first voltage search cycle at the output of the quadrature correlator 10 exceeds the threshold of the threshold unit 11, then the output of the inverter 18 will have a logic level O which will prevent the flow of the register 12 through the first element 19 reset pulses. In this case, level 1, the former in the first discharge of register 12, will go to its second discharge, thanks to the voltage drop at its counting input, which came from the output of the threshold unit 11. The output voltage of the threshold unit 11 will now prohibit the passage of pulses through the second element AND 20 to the third element AND 21 and the delayed scan will stop. Only the signal coming from the second output of the driver 16 will now pass to the output / switch 17, since level 1 will now only be at the control input of the switch 17, which is connected to the output of the second register bit 12o. Thus, the integration time of the processing result in the quadrature correlator 10 increases and becomes equal to T t, e. the search device for noise-like signals moves to the second stage of the first search cycle. If the threshold in threshold block 11 no longer occurs, the first element 19 at the moment of passing the waste pulse for register 12 will be open and the search device for noise-like signals will return to its initial state , will continue the search with the analysis time T of the first stage of the first search cycle. If, by the time of the next integration, the threshold in threshold block 11 is exceeded again, then 1 will already be in the third bit of the register 12 and the recheck of the signal availability will be made with an integration time Ilf greater than T (and T f, i.e. the device for searching noise-like signals will move to the third stage of the first search cycle.

In the search process, the PSSs search cycles, smaller K, impulses control516

nor by scanning for the delay of the reference signal from the output of the second element I-20 through the open fourth element AND 22 to the input of divider 23 to N. Therefore, every time after viewing the entire area of signal uncertainty, the delay is N from the output of divider 23 to the counter input 24 on To comes one. impulse. The status information of the counter 24 in the parallel binary code is fed to the input of the decoder 15 and, after being converted into one of the control signals, is sent to one of the K outputs to the driver 16 "

 Thus, if, after analyzing all the cells in the first search cycle, all detections turn out to be false and the signal is skipped after viewing the entire signal uncertainty region equal to N, the parameters of the subsequent cycle stages will be set in the shaper 16 optimal for a higher calculated interference / signal ratio (T V.4), etc. In the case of reaching the K-th search cycle, the optimal parameters of the stages of which are designed for maximum interference, these parameters remain unchanged on subsequent search cycles (t T), where t is t, 2c, o), since on the K-m output of the decoder 15 the logic level 1, closes the fourth element And 22, the flow of pulses to the input of the divider 23 stops, its state and the state of the counter 24 is fixed,

The last recheck of the signal availability is performed when 1 is in the last bit of register 12. This can occur on any search cycle, depending on the power of the interfering noise. The analysis of the last stage on any search cycle T. is equally the same, since this stage is the stage of tracking the signal. The analysis time of the last stage is optimal for a given time of tracking the signal without synchronization failure at the maximum interference the UL is designed for.

The rings of automatic frequency control (PAC) and tracking delay start to work when the delay coincides with an accuracy of up to N

06

the signal being fed to the signal inputs of the demodulator 3 and the phase discriminator 7 with the reference signal fed to them. In this case, the capture band of the A1GCH ring is chosen larger than the frequency band of the analysis of the penultimate stage of any search cycle, since the second condition for the operation of the AFC ring is the presence of a signal within the capture band of this circuit.

Register 12 is implemented in such a way that the output of the (L - 1) -th bit is connected to the input of an L-bit bit via an two-input OR circuit, the second input of which is connected to the output of the L-ro bit. Thus, after the device for searching for noise-like signals enters into synchronism, the level of the logical unit will not be erased from the incoming clock pulses in the shift register 12.

Claims (1)

Invention Formula A noise-like signal search device containing a sequentially connected controlled local oscillator, a mixer, a wideband amplifier, a quadrature correlator, a threshold unit, an inverter, a first And element, a shift register, a switch, a second K element, a third And element, a pseudo-random sequence generator whose output is connected to the second information input of the quadrature correlator, a demodulator connected in series, a narrow-band amplifier and a low-pass filter detector connected in series phase discriminator, correction amplifier and controlled clock generator, the output of which is connected to the second input of the third And element and clock input of the time interval shaper, as well as the fourth And element, time slot shaper outputs are connected to the corresponding information inputs of the switch, the output of which is connected to the reset input of the quadrature correlator and the second input of the first element I, the output of the threshold unit is connected to the second input of the second element A and both the information input of the shift register, and the reference input of the demodulator are connected to the first input of the phase discriminator, characterized in that, in order to reduce the search time for noise-like signals, serially connected pulse counting unit and the decoder are entered, the outputs of which are connected to the corresponding inputs time signal generator, while the output of the detector with a low-pass filter Connected to the input of the controlled local oscillator, the output of the pseudo generator random sequence connected to the first input of the phase discriminator, the second input of which is connected to the information input of the demodulator and connected to the output of the broadband amplifier, the output of the second element And connected to the first input of the fourth element And whose output is connected to the input of the frequency divider, and the second input of the fourth element And connected to the corresponding output of the decoder Compiled by V.Orlov Editor I.Segl iik Tehred L.Olninyk Order 1781 Circulation i98 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 Proofreader M.Samborsk Subscription