SU1651224A1 - Device for measurement of deviation of frequency from nominal value - Google Patents

Abstract

The invention relates to radio measurements and can be used to measure the frequency deviation from the nominal value. The Pel of the invention — improving accuracy — is achieved by introducing into the device an amplitude detector 9, a dividing unit 6 and making the resonator 2 tunable, which eliminates the dependence of the measurement results on the amplitude and perform measurements promptly. The device also contains a directional coupler 1, an amplitude detector 3, a selective amplifier 4, a synchronous detector 5, an indicator 7, a manipulation generator 8. 2 ill .- Q

Description

This invention relates to radio measurements and can be used in automatic frequency control and tuning systems.

The purpose of the invention is to improve the accuracy of measuring the frequency deviation from the nominal value.

Fig. 1 shows a block diagram of a device for measuring frequency deviation from a nominal value; figure 2 - resonance curves.

The device contains a series-connected directional coupler 1, a resonator 2, an amplitude detector 3, a selective amplifier 4, a synchronous detector 5, a dividing unit 6 and an indicator 7, a manipulation generator 8, a second amplitude detector 9. The output of the manipulation generator 8 is connected to the input of the synchronous detector 5 and the control input for the restructuring of the resonator 2, the input of the device through the directional coupler 1 is connected to the input of the resistor 2.

The device works as follows.

An input continuous signal through a directional coupler 1 with a transient attenuation of 3-7 dB is fed to resonator 2. Let the resonant frequency (x) of resonator 2 be lower than the nominal frequency GCL, and resonant frequency 0) higher.

The switching of the resonator 2 is carried out by sending the manipulation signals of the FM frequency from the oscillator 8. The voltage amplitudes at the output of the rf system

S3

HS

PLTORL I OOTHOT G 1 T RNNP r.chnNP Up)

.

Values С0 „. and C0 „„ bizki. On

Fig. 2, the frequency tolerance for the frequency from the nominal value D S0D0 (l and the limiting frequency deviation of the ASA transmitter that is monitored by the proposed device are rolled. And the detuning is measured from the nominal value

with „& o, + & og

F range 3-4 GHz is usually & CO noegi 40 MHz, As can be seen from Figure 2, its frequency of the monitored signal is equal to the nominal G) "&) ,, then Up, II p. At 00 and (I1 rg. I pi and vice versa at OEyy) Mirgs Up ,.

Thus, in the first half-cycle of manipulation of the Fw frequency signal from generator 8, the detector 3 receives a voltage with amplitude Up (and the second Up2 "Next, the video signal goes to the S.-optic amplifier 4 tuned to the frequency of the Fy manipulation signal. Voltage the output of the selective amplifier 4 is written by the expression

lV () K llflx,

where K, is the generalized coefficient characteristic of the coupling coefficient of the resonator with the detector, the transmission coefficient of the detector with the LF Ailtrom and the selective amplifier.

The output voltage depends not only on the frequency deviation from the nominal value, but also on the magnitude of the input voltage. The latter can be a significant source of error when the amplitude of the input voltage varies. To compensate for the effect of a change in U, is used as the second detector 9 detector with LF-Lilgrom,

In the synchronous detector voltage U- ,. is rectified, and a constant voltage is applied to the input of the relationship meter

 Vup. -11p2) To Kgie, C

Here K is the transmission coefficient of the synchronous pegector, Ampmtud Ucc

depends on the value of the voltage I pi pz and, in polarity, on the difference of Pr, -1 Pr (on the position of the measured frequency relative to CO c in Fig. 2).

At the output, the voltage is constant.

  U5X K.

where K is a generalized colder that takes into account the transmission coefficient of the directional coupler and the amplitude detector with the low-pass filter.

By selecting the gain of the selective amplifier, the equality of the number of transmissions is preserved.

five

0

five

0

45

K K

TO.

0

12

Thus, the input voltage of the device, which is supplied to the indicator 7, is a function of & SOC (LAN00 (consi; U (const)).

Claims (1)

The device allows you to automate the process and reduce the measurement time and can be used for continuous monitoring of the frequency deviation of electronic equipment A device for measuring the frequency deviation from the nominal value, containing a series-connected rrzonator, an amplitude detector, a selective amplifier and a synchronous detector, the second input of which is connected to the output of the manipulation generator, an indicator that, in order to DETECT, A sequentially connected directional coupler, a second amplitude detector and a dividing flare are entered into it, the second input of which is connected to the output of the synchronous detector, and the output is connected to the indicator input, the input The device “through a directional coupler is connected to the input of the resonator, the control input of which is connected to the output of the manipulation generator. prUp. Fie.2