SU1211663A1 - Apparatus for processing signals of doppler navigator - Google Patents

Abstract

The invention relates to the field of radio engineering and can be used to process signals from a Doppler velocity meter. The purpose of the invention — an increase in measurement reliability — is achieved by selecting Doppler bursts of pulses. The device contains a filtering unit 1, an amplitude selection unit 2, a time delay unit 3, triggers 4, 10 and 11, a reference sequence generator 5, an AND-NE logic element 6, a counting pulse generation unit 7, a Doppler frequency measurement unit 8, a counter 9. To achieve this goal, a third trigger 1 is added to the device. Operation of the device is explained in the time diagrams in the description of the invention. 2 Il. i a 9d 00

Description

The invention relates to radio engineering and can be used to process signals from a Doppler velocity meter.

The purpose of the invention is to increase the reliability of the measurement by selecting Doppler pulse shells.

FIG. 1 shows a functional diagram of the device; in fig. 2 diagrams for his work.

The device contains a radium filter unit 1, an amplitude selection block 2, a time delay block 3, a first trigger 4, a reference generator 5, an element 6, a counting pulse forming unit 7, a Doppler frequency measuring block 8, a counter 9, a second trigger 10, the third trigger 11.

In the device, the filtering block I and the amplitude selection block 2, the first trigger 4 and the reference sequence generator 5, the counting pulse generation unit 7 and the Doppler frequency measuring block 8 are connected in series. The output of the Doppler frequency measurement unit 8 is connected to the setup inputs of the first 4, second 10, third 11 triggers, counter 9, the first input of the counting pulses forming unit 7 and the second input of the amplitude selection unit 2, the output of which is connected to the input of the time delay unit 3, the second input block 7 of the formation of the counting pulses and the first input element AND-NOT 6, the output of which is connected to the first information input of the first trigger 4, the zero input of the counter 9 and the information input of the third trigger 1. The output of block 3 time delay is connected to the second information input of the first trigger 4. The output of the generator 5 of the reference sequence is connected to the counting input of the counter 9, the output of which is connected to the information input of the second trigger 10. The output of the last is connected to the second inputs of the AND-6 element and the Doppler frequency measuring unit 8 , the third input of which is connected to the output of the third trigger 11.

The device works as follows.

The signal of the Doppler frequency f through the filtering unit 1 is fed (Fig. 2a) to the first input of the unit 2 am

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bulk selection, at the output of which a sequence of pulses is formed (Fig. 26). This sequence is shifted by time

5 of the holder K in the block 3 of the time delay enters (fig. 2d) on trigger 4, which is tilted by the falling edge of the pulse to the position of a logical unit (fig. 2d)

10 and starts the generator 5 of the reference sequence, at the output of which a pulse sequence is formed (Fig. 2e), which is counted by counter 9

15 (Fig. 2e). The overflow signal from its output overturns the trigger 10, the output of which forms the leading edge of the gate-pulse (Fig. 2g), which is in the form of a logical unit

20 comes from the output of the trigger 10 to the second input element AND-NOT 6, the first input of which receives pulses from the output of block 2 of amplitude selection (Fig. 2b). Pass through 25 element AND-NOT 6 (Fig. 2h),

the pulses are reset to the zero state of the counter 9 (Fig. 2e) and the trigger 4 (Fig. 2d), preventing the formation of an overflow signal in

30 counter 9. The overflow signal is formed only when there are no 9 pulses from the output of amplitude selection unit 2 at the moment of counter operation (Fig. 2b, e). In this case, the overflow signal (Fig. 2e) resets the trigger 10 to the initial state (Fig. 2g) and at its output forms a strobe pulse T (Fig. 2g), which is fed to the second

The Q input of the Doppler frequency measurement unit 8, the first input of which receives pulses from the output of the counting pulse forming unit 7, whose number is equal to

 lu Doppler frequency periods. In block 8 of the Doppler frequency measurement, the Doppler frequency is calculated using the formula

f

50 3 t:

where N is the number of Doppler frequency periods

At the time of the calculation (Fig. 2d) 55, the signal from the output of the Doppler frequency measurement unit 8 locks the time selection unit 2, and at the end of its triggers 4, 10 and II and

a block 7 for forming counting pulses to the initial state.

If the duration of the Doppler burst of pulses TC (Fig. 2b) is longer or equal to the overflow time T (Fig. 2e) required to replenish counter 9, then the duration of the generated pulse gate T is equal to the duration determined by the true number of periods of the Doppler frequency. The accuracy of the formation is determined by the stability of the generator 5 of the reference sequence. The delay time of block 3 of the time delay is chosen constant and small, since the purpose of the delay in the device is to eliminate the coincidence of the resetting moment of the trigger 4 to zero by the pulse from the output of the AND-NE 6 element (Fig. 2h) with the moment of setting the trigger 4 to the position of a logical unit (Fig. 2d) on the falling edge of the incoming to. trigger input 4 pulse output unit 3 time delay.

If the duration of the Doppler packet of TPI is less than the overflow time (see Fig. 2 for the case of fa,) j, then the duration of the generated strobe-pulse is not equal to the duration determined by the number of periods of the Doppler frequency (in this case, fа). Thus, during processing, only packs longer than the overflow time should be used.

In order to exclude non-erroneous results, reducing the reliability of the measurement, it is necessary to exclude results in which T T. For this, trigger 11 is entered into the device. If the time of the TC (Fig. 26) is longer than the time Tj, {Fig. 2g), then at the output of the AND-NE 6 element, an impulse is necessarily formed (Fig. 2h), which sets the trigger 1I to the position of a logical unit on the code. If the condition T1 n is met (see. 2 for the case fq-), then the output of the trigger I1 remains a logical zero. The signal from the trigger output M is fed to the input of the Doppler frequency measurement unit 8, where it is used to select false results.

5 10 15 20 25

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The trigger 11 is reset by a signal from the output of the Doppler frequency measurement unit 8.

In this way, the reliability of the measurement in this device is improved.

Claims (1)

Invention Formula A signal processing device for a Doppler velocity meter, containing a series-connected filtering unit and an amplitude selection unit, the output of which is connected to the first input of the NAND element, the output of which is connected to the counter zeroing input, the time delay unit, the first trigger and a reference sequence generator, a series-connected count pulse forming unit and a Doppler frequency measurement unit, the output of which is connected to the first input of the shaping unit and counting pulses, the second input of the amplitude selection unit and the installation inputs of the counter and the second trigger, the output of which is connected to the second inputs of the Doppler frequency measuring unit and the NAND element, characterized in that, in order to improve reliability, a third trigger has been entered into it the input of which is connected to the output of the unit is measured. - ki Doppler frequency, the third. the input of which is connected to the output of the third trigger, the information input of which is connected to the output of the NAND element and the first information input of the first trigger, the setpoint input of which is connected to the weighted course of the Doppler frequency measurement unit, and the second information input of the first trigger of the theory with the output of the block, the delay time, the input of which is connected to the output of the amplitude selection block and the second input of the block fop oprovani counting pulses, while the output of the generator reference sequence is connected to the counting input of the account eTchika, the overflow output of which is connected with the information input of the second trigger .. with g % YAP  t i t PP Ta - L , / t . l 7b