SU1378080A2 - Receiver of broadband linear rf-signals - Google Patents

Abstract

The invention relates to radio and is complementary to the invention according to the author. St. No. 771901. The purpose of the invention is the elimination of receiving redundant information. The device contains receiver 1, mixers 2 and 3, local oscillators 4 and 5, compression filters 6 and 7, decision block 8, frequency detector 9, differentiation block 10, driver 11 pulses, narrow-band filter 12, amplitude detector 13, generator 14 counting pulses, block 15 matches. The counter 16, the keys 17, 22 and 23, the storage unit (ST) 18, the code comparison unit 19, the additional differentiating unit 20 and the valve 21. In mixers 2 and 3, the intrapulse filling frequency of the received linear frequency modulated (LFM ) signal to the intermediate frequency region. From the transformed by the mixer, 3 chirp signals using blocks 12-16, 20, and 21 provide information on the rate of change of the chirp frequency of the signal. Block 19 compares the code, respectively. of this information, with the code measured in the previous period and recorded in ST 18. If the codes are not equal, then according to the signal of block 19, keys 17, 22 and 23 are opened. In addition, a new code value is entered in ST 18 and the information signals are compressed filters 6 and 7 in the decision block 8. Introduced blocks 12-23. 1 il. with S (L

Description

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The invention relates to radio engineering and can be used in radio communication systems and radio telemetry.

The purpose of the invention is to eliminate the reception of redundant information.

The drawing shows a structural electrical circuit of the proposed device.

The device contains a receiver 1, mixers 2 and 3, the local oscillators 4 and 5, compression filters 6 and 7, a decisive block 8, a frequency detector 9, a differentiating block 10, a pulse shaper 11, a narrowband filter 12, an amplitude detector 13, a generator. 14 counting pulses, a coincidence block 15, a counter 16J, the first key 17, the locking block 18, the block 19 of code comparison, the additional differential block 20, the valve 21, the second and third keys 22 and 23.

The device works as follows.

Received periodic linearly - frequency modulated (LMF) signal

Uc (t) (2fTfj.t + t2 + t /); n tfi,

amplitude, initial phase and duration of the signal;

the value of the frequency at the beginning of the pulse is the rate of change of the frequency inside the pulse.

dfa - frequency deviation, from receiver output 1 goes to the first inputs of mixers 2 and 3, to the second inputs of which, respectively, from the outputs of the local oscillators 4 and 5, are supplied, voltage

UT- (t) V, .cos (2ffT t + if);

ten

15

20

25

where v, lf,

 AND

thirty

. R

 35

40

VT needle "-cos (+

T t 1

In mixers x 2

r,).

and 3 intrapulse frequency is shifted along the frequency axis to the intermediate frequency region fpr. Keys 17, 20, and 21 are always locked in their original state. The frequency-converted chirp signal from the output of mixer 3 is fed to the input of narrow-band FILTER 14, where it is converted into a sequence of radio pulses. Bandwidth

45

The radio pulses from the output of the narrowband filter 12 are fed to the input of the amplitude detector 13, where their envelope V is distinguished. The duration of the video pulses associated with the rate of change of the chirp frequency is as follows

3 / 3f /.

The resulting video pulses from the output of the amplitude detector 13 are fed to the input of the additional differentiating unit 20 and the first input of the coincidence unit 15, to the second input of which the output of the generator 14 is fed to counting pulses. At the output of the additional differentiating unit 20, short polar impulses are formed, which are fed to the input of the valve 21 (unipolar). Valve 21 transmits only positive short pulses. These pulses are applied to the reset inputs of the counter 16 and the code comparison block 19, dropping their contents to zero. Therefore, in each repetition period, the indicated pulses prepare the counter 16 and the code comparison block 19 for operation. In addition, the pulses read the information contained in the storage unit 18 into the code comparison unit 19. The number of counting pulses, proportional to the rate of change of the signal frequency, y, is calculated

counter 16 and arrive at the first input of block 19 of code comparison, the second input of which is supplied with the code of the previously measured rate of change of the signal frequency from the output of block 18,. In the initial state in the memory of block 18, there is no information. If the compared codes are not equal, then the code comparison block 19 generates a voltage that is supplied to. the control inputs of the keys 17, 22 and 23, opening them. Then the code of the rate of change of the signal frequency, measured in the first repetition period, through the public key 17 enters into 0 the storage unit 18, where it is recorded in its memory. In this case, the old result is erased, and the new one is recorded. Signals received by receiver 1 after frequency conversion

Af-band filter 12 selects -55g mixers x 2 and 3 through open

with significantly less power-keys 22 and 23 arrive at compressing

the possible width of the spectrum (deviation of the hour-filters 6 and 7. Simultaneously the chirp signals dfij) of the received chirp signals.

fillers from above 1 mixers 2 and 3 pos0

five

0

five

0

five

0

five

The radio pulses from the output of the narrowband filter 12 are fed to the input of the amplitude detector 13, where their envelope V is distinguished. The duration of the video pulses formed is related to the rate of change of the chirp signal frequency as follows

3 / 3f /.

The resulting video pulses from the output of the amplitude detector 13 are fed to the input of the additional differentiating unit 20 and the first input of the coincidence unit 15, to the second input of which the output of the generator 14 is fed to counting pulses. At the output of the additional differentiating unit 20, short polar impulses are formed, which are fed to the input of the valve 21 (unipolar). Valve 21 transmits only positive short pulses. These pulses are applied to the reset inputs of the counter 16 and the code comparison block 19, dropping their contents to zero. Therefore, in each repetition period, the indicated pulses prepare the counter 16 and the code comparison block 19 for operation. In addition, the pulses read the information contained in the storage unit 18 into the code comparison unit 19. The number of counting pulses, proportional to the rate of change of the signal frequency, y, is calculated

counter 16 and arrive at the first input of block 19 of code comparison, the second input of which is supplied with the code of the previously measured rate of change of the signal frequency from the output of block 18,. In the initial state in the memory of block 18, there is no information. If the compared codes are not equal, then the code comparison block 19 generates a voltage that is supplied to. the control inputs of the keys 17, 22 and 23, opening them. Then the code of the rate of change of the signal frequency, measured in the first repetition period, through the public key 17 enters into 0 the storage unit 18, where it is recorded in its memory. In this case, the old result is erased, and the new one is recorded. Signals received by receiver 1 after frequency conversion

Filters 6 and 7. Simultaneously chirp signal

The bursts from the top of the mixers 2 and 3 are fed through the public keys 22 and 23 to the frequency detector 9 and are converted to the voltage of the corresponding form. This voltage is applied to the input of the differentiating unit 10, the output of which produces rectangular pulses. The output of the transmitter 11 generates pulses at the instants of time corresponding to the instants of the change in the sign of the slope of the functions of the frequency modulation of the chirp signals. These pulses, together with the information pulses from the outputs of the compression filters 6 and 7, are fed to the corresponding inputs of the decision unit 8, providing clock synchronization at the decision reception.

On the second and subsequent repetition periods of the received chirp signal, the compared codes are equal on the second; block 19, the comparison of the voltage codes is absent, the keys 17, 22 and 23 are closed. Consequently, only in the first repetition period of the received chirp signal does it arrive, after conversion and compression, to decision block 8, and the code of the measured rate of change of the signal frequency is recorded in the storage unit 18.

Q 5

0

“25

Claims (1)

Invention Formula A device for receiving broadband signals with linear frequency modulation by aut. St. No. 771901, t - characterized in that, in order to eliminate the reception of redundant information, a series-connected narrowband filter, an amplitude detector, a coincidence unit, a counter, a first key, a memory of the 1st block, a code comparison unit and a second key, and a third key are introduced , a generator of counting pulses, an additional differential unit, a valve, the outputs of the mixers are connected to the inputs of the corresponding compression filters and the inputs of the frequency detector through the corresponding second and third keys, the output of the second mixer is with the input of the narrowband filter, the output of the amplitude detector through a series-connected differential unit and a valve connected to the reset inputs of the counter and code comparison unit and the read input of the storage unit, the output of the counting pulse generator is connected to the second input of the coincidence unit, the output of the code comparison unit is connected to the second inputs of the first and. third keys.