SU995339A2 - Device for monitoring carrier frequency - Google Patents

Description

(54) DEVICE FOR TRACKING FROM A CARRING FREQUENCY

one

The invention relates to a communication technique and can be used to recover a carrier frequency in a single sideband demodulator.

According to the main author. St. No. 926770, a device for tracking a carrier frequency is known, comprising a receiver, a phase locked loop (PLL), including a tunable generator and a phase detector, the second input of which is connected to the output of the receiver, as well as a series-connected delay line, averaging unit and an additional tunable generator, and a serially connected threshold driver, control unit and switch, to another input of which) a clock generator is connected, with the inputs of the delay line and the threshold form The universalizer is connected to the output of the phase detector of the PLL, and the output of the key is connected to the control input of the averaging unit 1.

A disadvantage of the known device is the relatively small range of monitored frequency detunings due to the possibility of capturing for the spectral components of the sideband speech signal.

The purpose of the invention is to increase the range of tracked detuning.

To achieve this goal, in a well-known device for tracking the carrier frequency, the control unit and the key are connected in series through the additionally entered statistical signal recorder of histograms of signal durations, the other input of which is connected to

10 output delay line.

The block of the statistical recorder of histograms of signal durations is made in the form of parallel channels, each of which contains successively connected threshold block, a key and an integrator with a reset, wherein the inputs of the threshold blocks of all channels are combined and are the information input of the block of the statistical recorder g of duration logs signal outputs threshold

The 20 blocks are connected to the inputs of the block determining the current zone number, the output of which is connected to the first input of the first comparison element, the control inputs of the keys are combined with the first input of the coincidence element and are the control input of the statistical block, the recorder of histograms of signal durations, the reset inputs of the integrators connected to the output of the second reference element, to the first input of which the reference voltage is applied, the outputs of the integrators are connected to the inputs of the maximum value selection unit, the output of which is connected nen to a second input of the second comparing element and to block inputs determine the zone number with the maximum level, the output of which is connected to the second input of the first comparing element whose output is connected to the second input of the coincidence element, whose output is the output of the statistical histogram registrar signal durations.

The unit of statistical recorder histograms of the device signal duration determines how often one or other instantaneous frequency values occur at the receiver output of the pilot signal, selects the maximum frequency corresponding to the frequency of the pilot signal (because the frequency of the pilot signal due to its determinism is relatively changes slowly over time, and the instantaneous frequency of the spectral components of the speech signal, due to its random structure, Typfei takes on different values over time) and forms t resolutions Display resolution signal averaging, if the instantaneous frequency at the output of the pilot signal of the receiver is close to the maximum relative frequency, and averaging the inhibiting signal if the difference significantly.

The device prohibits averaging if the spectral components of the speech signal are present at the output of the pilot signal, which eliminates the possibility of a false capture of the device (the device retains the previous frequency value) and the range of monitored detunings is expanded.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 is a block diagram of a statistical recorder of histogram of signal duration (BSRGDS).

The device contains a receiver 1, a phase locked loop (PLL), including a tunable digital-type oscillator 2 and a phase detector 3, the second input of which is connected to the output of receiver 1, and a chain of delays connected in series 4 is connected to the output of phase detector 3, unit 5 averaging and an additional tunable digital type generator 6, as well as a threshold driver 7, the output of which is connected to the input of control unit 8, the output of which is connected to the control input of BSRGDS 9, are informational whose input is connected to the output line 4 delay, the output BSRDGS 9 through key 10

connected to the control input of the averaging unit 5.

BSRDGS 9 consists of (according to the number of partition zones) parallel channels, each of which contains series-connected threshold block 11, key 12 and integrator 13 with a reset. The inputs of the threshold units 11 are combined and are the information input of unit 9, the outputs of the threshold units 11 are connected to the inputs

block 14 for determining the current zone number, the output of which is connected to the first input of the first comparison element 15. The control inputs of the keys 12 are combined with the first input of the matching element 16 and are the control input of the block 9. The reset inputs of the integrators 13 are connected to the output of the second comparison element 17, the first input of which is supplied with the reference voltage imax | B1 of the integrators 13 connected to the inputs of the block 18 maximum selection

.. value, the output of which is connected to the second input of the second comparison element 17, and to the inputs of the zone number determining unit 19 with the maximum level, the output of which is connected to the second input of the first comparison element 15, the output of which is connected

5 to the second input of the coincidence element 16, the output of which is the output of block 9. The device operates as follows. Received by the receiver 1 the amount of noise and the radio pulse signal is amplified, converted to the frequency and distorted by the narrow band of the receiver, fed to one of the inputs of the phase detector 3. The output signal of the phase detector of the PLL ring, depending on the frequency of the input signal, is fed to the line 4 steps, where it is delayed by time t, and then filtered by averaging unit 5. The output signal of the phase detector 3 is also fed to the threshold driver 7, the output voltage of which is equal to "1 if the signal-to-noise ratio at the output

0 receiver 1 exceeds the specified value, and is equal to "O, if the signal-to-noise ratio at the output of receiver 1 is less than the specified value.

The control unit 8 shortens the video pulses coming from the threshold shaper by time 7 (from the moment of transition of the pulse from “O to“ 1). The received control signal is fed from control unit 8 to control input of BSRDGS 9, to the information input of which the signal of phase detector 3 delayed by delay line 4 is sent.

The range of change of the output signal of the phase detector 3 (and, therefore, the tracking band of the PLL ring) is divided into N equal zones with the help of threshold blocks 11. The width of each zone is equal to U,

The threshold unit 11 of the i-ro channel provides the level of a unit amplitude if the signal level at its input lies in the response area of this device.

(i-1) UK With Ubx iUx.

The keys 12 pass the signals from the threshold blocks 1 to the corresponding integrators 13 without changing if the signal from the output of control unit 8 is equal to "U, and prohibit the passage of signals if the signal from the output of control block 8 is equal to" O (the integrators retain the corresponding the accumulated values of Ui) The output signals of all threshold blocks II are also fed to the block 14 for determining the current zone number in which the input level of the BSRDGS 9 is currently located. The block 19 for determining the zone number with the maximum level is determined integrator number 1max whose output signal has the highest level. The current zone number i, which is output by the current zone number determination unit 14, is compared by the comparison element 15 with the zone number with the maximum level of the flag if the condition:

/ -W / m, where t Oh,

the comparison element 15 generates the signal "1, if / i-1 | vks /, then the signal" O is generated. The output signal of the comparison element 15 is fed to the first input of the coincidence element 16, the second input of which receives a signal from the control unit 8. The output signal of the coincidence element 16 is equal to "1, only in the case of the presence of" 1 at the output of control unit 8 (which means that the signal-to-sound ratio exceeds a predetermined level) and the presence of "1 at the output of the comparison element 15 (indicating the presence of detector 3 pilot signal).

In order to eliminate the overflow of integrators 13, the maximum value selection unit 18 selects the maximum level from the output levels of the integrators 13 and compares in the comparison element 17 with the image which, if exceeded, the comparison element 17 outputs a signal to the reset inputs of the integrators 13. In this case, all the integrators 13 are reset. to values Uai KUi, where О К 1 The signal from the output of BSRDGS 9 arrives at key 10, to the other input of which clock pulses are applied. The output signal of the key 10 controls: the operation of the averaging unit 5. In the presence of clock pulses, the averaging unit 5 filters the signal from the output of the delay line 4 (tracking mode). In the absence of clock pulses at the output of key 10 (memory mode), the output of block 5 of averaging preserves the previous value of the signal at the moment when the key is closed.

The output of averaging unit 5 controls the frequency of the additional digital tunable generator 6 with a tuning characteristic that repeats the characteristic of the digital tunable generator 2.

Let the pilot signal present in the pauses of speech and the speech signal arrive at the input of receiver 1. Then at the moments when the signal-to-noise ratio exceeds the specified value, the control unit 8 outputs a signal equal to "1. At the same time, the BSRBD is processing the input signal. In integrators 13 there is an accumulation of unit increments.

The maximum signal level has an integrator whose number corresponds to the zone number in which the pilot frequency is located.

In case the current frequency value is in the zone with the number from -t) to (IMSKC n), the device performs tracking mode.

If the current frequency value is in the zone with a number different from (1 max T1) - (max + hp), the device is switched to the memory mode. Therefore, interference from the speech path does not cause the device to go to the frequencies of the spectral components of the speech signal, and only translates it into memory mode.

Therefore, the device for tracking the carrier frequency provides a wider range of tracked detunings.

Claims (2)

1. Device for tracking the carrier frequency according to the author. St. No. 926770, characterized in that, in order to increase the range of monitored frequency detunings, the control unit and the key are connected in series through the additionally entered statistical signal recorder of histograms of signal durations, another input of which is connected to the output of the delay line. 2. A device according to claim 1, characterized in that the statistical recorder block of histograms of signal durations is made in the form of parallel channels, each of which contains a series-connected threshold block, a key and an integrator with a reset, and the inputs of the threshold blocks of all channels are combined the information input of the statistical recorder block of histograms of signal duration, the outputs of the threshold blocks are connected to the inputs of the block determining the current zone number, the output of which is connected to the first input of the th comparing element control inputs of keys combined with a first input of the coincidence and are a control input unit statistical duration histograms registrar signal inputs Throw