SU1709266A2 - Linear frequency-modulated oscillation frequency-deviation meter - Google Patents

Abstract

The invention can be used in radar stations of continuous radiation. The purpose of the invention is to reduce the measurement time of the deviation of the linear-frequency-modulated oscillation by including in the device for measuring the frequency deviation of the chirp oscillations of the frequency divider 16. The device also contains a sawtooth voltage generator 1, a controlled generator 2, a phase detector 3, a reference generator 4, a key 5, a low-pass filter 6, a DC amplifier 7, a pulse shaper 8, a normalization unit 9, a display unit 10, a crystal oscillator 11. With the arrival of the control pulse, the phase synchronization system of the controlled oscillator 2 is disconnected and the sawtooth voltage oscillator 1 is triggered, rearranging its frequency. At the output of the phase detector 3, an error voltage appears, which is fed to the driver of 8 pulses at the moments of voltage passing through the level "O". In block 9 of the normalization during modulation time T mod, the number of pulses K and N are calculated, respectively, from the output of the driver 8 and, through a divider 16, from the output of the crystal oscillator 11, the phase proportional to the raid Atf > & v \ 1mod. In the additional time interval T dop, the K-Cd / N division is performed, where Cd is the scale factor. The result is displayed in the display unit 10. The decrease in the pulse counting frequency N due to the divider 16 necessitates a decrease in Kd, which reduces Tdop = K-Kdx x1 / ficB. where fic8 is the frequency of the quartz oscillator 11. 2 Il. SOCI VI o Yu o o o > & goFig ^ ulraV ^ enil

Description

The invention relates to radio measurements, is intended for use in radar stations of continuous radiation and is an improvement of the known device described in the author. St. USSR № 1190281.

According to the main author. St. Nb 1190281 is known a device comprising a sawtooth generator, a controlled oscillator, a phase detector, a reference oscillator, a switch, a low-pass filter, a DC amplifier, a pulse driver, a normalization unit, a display unit, and a crystal oscillator, the normalization unit comprising a control unit , reversible counter, counter divider, first element 2И, binary counter, block of elements NOT, binary counter with prerecord information, second element 2I, delay element, binary decimal tchik and memory unit.

In this device, the measurement of frequency deviation involves two steps. At the first stage, the reversible counter and the binary counter of the rationing unit calculate, respectively, the number K of pulses from the output of the pulse former (number of phase raids in l: radians) and the number N of counts of the counting frequency fKB from the output of the crystal oscillator during the control pulse (modulation time hmod At the second stage, in the additional time interval T dop, the phase shift K is divided during the modulation time by the modulation time tMofl. which corresponds to the value of the frequency deviation Sd.

Hmod

However, in the known device, the measurement time is great, especially with high measurement accuracy and large bases of the measured signal. Since the division is implemented on a binary counter with pre-recording of information by counting the number of bursts of pulses recorded at the pre-recording input (the number of pulses in a burst is N), in the additional time interval, and the value of the additional time interval

K Kde - Tkv d-,

where T | st -; the period of the counting frequency IMTV

pulses from the output of the quartz generator:

fxB

Kdep is the r-divisor ratio of the counter divider;

L is the price of the lower bit of the display unit, determined by the required measurement accuracy, Hz.

The purpose of the invention is to reduce the measurement time of the frequency deviation of the line1 of the night-frequency-modulated oscillation.

To achieve the goal, the rationing unit of the device for measuring the frequency deviation of the linear-frequency-modulated oscillation contains a looped controlled oscillator, a phase detector, a key, a low-pass filter, and a DC amplifier, a sawtooth generator, the output of which is connected to the second input controlled oscillator, the reference oscillator, the output of which is connected to the second input of the phase

5 of the detector, a pulse generator connected in series, the input of which is connected to the output of the phase detector, a rationing unit and a display unit, a crystal oscillator, the output of which is connected

0 with the second input of the normalization unit, the third input of the normalization blocks, the second input of the key, the input of the sawtooth generator on. the yarns are connected to the control pulse bus, and the ration unit

5 contains a control unit, a reversible counter, a counter divider, the first and second elements 2I, a binary counter, a block of elements NOT, a binary counter with preliminary recording of information,

0 delay element, binary-decimal counter, memory unit, the first output of the control unit is connected to the subtraction input of the reversible counter, the second output of the control unit is connected to the first input of the binary counter, the third output of the control unit is connected to the first input of the first element 2I and the first the input of the second element 2I, the fourth output of the control unit is connected to the second input of the reversible counter, to the third input of the binary counter, to the first input of the binary counter with preliminary recording of information, to the first input of the double a decimal counter, with the first input of the counter divider, the fifth output of the control unit is connected to the first input of the memory block, the sixth output of the control unit is connected to the second input of the binary counter with pre-recording information and the second input of the counter divider, first, second and the third inputs of the control unit are the inputs of the normalization unit, the fourth input of the control unit is connected to the output of the reversible counter, the output

5, the counter divider is connected to the input of the addition of the reversible counter and to the second input of the first element 2I. the output of the first element 211 is connected to the third input of the counter separator, the outputs of the binary counter are connected to the inputs of the block of elements NOT, the outputs of the block of elements are NOT connected to the inputs of the binary counter with pre-recording information, the output of the binary counter with pre-recording information is connected to the second input of the second element 2I and with the second input of the binary-decimal counter, the output of the second element 2I is connected to the input of the delay element, the output of which is connected to the third input of the binary counter with By recording the information, the outputs of the binary-decimal counter are connected to the inputs of the memory unit, the output of the memory unit is connected to the output of the normalization unit, a frequency divider is added, the input of which is connected to the second input of the control unit and the output is connected to the second input of the binary counter.

FIG. 1 shows a functional diagram of the device; Fig. 2 is a functional diagram of the rate unit.

The device contains a sawtooth voltage generator 1, a controlled generator 2, a phase detector 3, a reference generator 4, a key 5, a low-pass filter 6, a DC amplifier 7, a pulse shaper 8, a normalization unit 9, a display unit 10 and a crystal oscillator 11 .

The normalization unit 9 contains the control unit 12, the reversible counter 13, the counter divider 14. the first element 2И 15, the frequency divider 16, the binary counter 17. the block of elements NOT 18. the binary counter 19 with the preliminary recording of information, the second element 2 and 20, the delay element 21 , binary decimal counter 22 and memory block 23.

The device works as follows.

Before the arrival of the control pulse, the key 5 is open. If the voltages from the outputs of the controlled oscillator 2 and the reference oscillator 4 are not equal in frequency and phase, then the output of the phase detector 3 is a misalignment voltage that through switch 5. low pass filter 6, amplifier 7 direct current enters controlled oscillator 2, keeping the difference of frequencies and phases between the controlled and reference oscillator signals, equal to zero. Thus, in the absence of modulation, there is no signal at the output of phase detector 3.

At the time of arrival of the control pulse key 5, the phase-locked loop of the frequency is broken, the generator 1 of the saw-tooth voltage is started, the frequency of the signal at the output of the controlled oscillator 2 increases linearly

Actually, and from the output of the phase detector 3, a differential frequency signal is fed to the driver of 8 pulses, which generates pulses at the moments of voltage transition 5 of the low-frequency sinusoid through the O level.

With the arrival of a control pulse, its leading edge from the fourth output of control unit 0 12 is fed to counters 13, 14. 17.19 and 22 to set them to state O. Then, during the control pulse, to binary counter 17 from the crystal oscillator 11 through frequency divider 16 5 number of pulses N is recorded, which is simultaneously fed from the output of binary counter 17 in the form of a binary parallel code through a block of elements HE 18 in the reverse code to a binary counter 19 with preliminary recording of information. At the same time, during the control pulse in the reversible counter 13, the number of pulses generated by the imaging unit 8 and 5 pulses are counted in the reverse code in the subtraction input.

After the termination of the control pulse, the pulses from the crystal oscillator 11 through the control unit 12 are fed to the counter divider 14 and after dividing with the coefficient Ked from its output are fed to the input of the reversing counter 13. The subtraction of the number K recorded in the counter for the subtraction input occurs. Simultaneously the pulses of the crystal 11 is fed to the counting input of a binary counter 19c by pre-recording information in which the counting is conducted from the number NB of the reverse code to overflow. Number of overflow pulses M is counted up by a binary-0 with a counter 22 until the overflow pulse of the reversing counter 13 arrives, by which the code of the number M is rewritten into memory block 23. From the output of the last information, a parallel code enters the display unit 10. Since the time until the overflow counter 13 overflows is equal to Tkb Ked-K and the time until the binary counter 19 overflows with the preliminary recording of information

0 is equal to Tka Nf the number of overflow pulses

 Ked K u

-bi

(Beating.

N

Tkv

1MOD

The introduction of a frequency divider 16 with a Kdr dividing factor reduces the number N of pulses counted by binary counter 17 for the time T mod. N N / KDH that in

the turn makes it necessary to reduce the division ratio of the Cad counter 14 Cd Cd / Cdc divider to preserve the truth of the division, i.e. the number of overflow pulses M and M dual counter 19 with pre-recording information before and after the introduction of the divider frequency 16, respectively

I-K-Ked k-Ked-k

dh

1and

 M,

TQN KCD

Therefore, the value of the additional time interval T dop after turning on the divider 16 frequency

To Ked Tkv Tdop

TDOP ° K X T

Cdc

dh

will be reduced in cdf times compared to the value before it is turned on.

A similar effect can be obtained by including in the prototype a second lower frequency crystal oscillator, the output of which is connected to the second input of the slider counter instead of the pulses fed through this input from the output of the first crystal oscillator.

Claims (1)

Invention Formula A device for measuring the frequency deviation of a linear-frequency-modulated oscillation by author. St. Mg 1190281, characterized in that, in order to reduce the measurement time of the frequency deviation of the linear-frequency-modulated oscillation, a frequency divider is inserted into the normalization unit between the second input of the control unit and the second input of the binary counter.