SU599225A1 - Close frequencies comparator - Google Patents

Description

The invention relates to a radio metering technique and is intended to measure short time of first frequency instability and to measure close frequencies of two highly stable sources, for example, quantum generators. Frequency comparators are known comprising a reference frequency source, a two-stage sequential multiplier device, and a frequency converter l. A large number of multiplication, mixing, and division cascades increase the intrinsic noise of the measuring and reference channels and ultimately limit instrumental accuracy of the instruments. Closest to the present invention is a close frequency comparator containing a block of measured frequency, a mixer, a frequency divider, a counting block, a multiplier, and a Shaper of counting pulses 2j. A disadvantage of the known device is the dependence of the measured result on the instability of the local oscillator on the deviation of its frequency from the nominal value, as well as the complexity of the formulas for calculating the measurement results during operation during the processing and the inverse dependence of the measurement results on the frequency change: the lower the meter reading. In order to improve measurement accuracy, a near frequency comparator containing serially connected measured frequency unit, mixer, frequency divider and counting unit, serially connected multiplier and counting pulse generator, the output of which is connected to the second input of the counting unit, are additionally connected in series the first additional frequency divider and additional mixer, the second additional divider, the output of which is connected to the input of the first additional frequency divider and second th input of the mixer, the output of the additional frequency mixer is coupled to the input of the measured channel frequency and a second input of the additional mixer input coupled c- second additional divisor, and a second input of the multiplier input of the counting pulses. The drawing shows a structural electrical circuit of the proposed device. The close frequency comparator contains a measured frequency block 1 consisting of a mixer 2 and a frequency multiplier 3.

4 frequency divider, 5 mixer, div) gel b frequency, 7 mixer, multiplier 8, frequency divider 9, counting unit 10 and driver 11.

The device works as follows.

Harmonic signals measured

(f) and the reference (fo) frequencies are fed to the inputs of blocks 1 and 4. The signal of the measured frequency is fed to one input of mixer 2, to the other its input comes a signal from the output of additional mixer 5, in which the frequencies f and и are mixed.

The output of the mixer 5 receives a signal with a frequency

P

 1 o e (m-i)

(one)

e is the division factor of l frequency;

DR (- deviation of the reading device.

At the output of mixer 2, a signal is received

 v..p.-i

  E (.il

C & (t-1) C2)

The signal from the output of the mixer 2 is fed to the input of the multiplier 3 frequencies m times. From the output of the multiplier 3 frequency, the signal with frequency F m - ° C is removed (the TA signal which is fed to the input of mixer 7 and the signal from the output of frequency divider frequency O / I to the output of mixer 7 receives the signal of the difference frequency e (tn- i) Next, the signal with frequency Fj is fed through a frequency divider 9. The division factor f is to the counting unit 10. The frequency of the counting pulses is applied to the other input of which from the driver .11 Mfp or o, where M is the multiplication factor of frequency 8 The counting unit records the number of counting pulses, p ohod boiling for the period T .. M "1tM nd (m-1) counting unit kloneniepokazany

from MO when changing the frequency i f, caused by the presence of d P (., you can write

d N N - N,

(.9)

lm M-e (m - IVf o (m-iUArJ- - -2 2

nm (m - (-Em Af

(10) o-hnCm-i) t-AF.

g (m-i) e- d PC,

DM

(11) f.

here

AN f o

-TO,

dr

"2) N

N m (m-i) e

de

con6i

to (13)

tnCm-Oe

From expression (12) it can be seen that the formula for the relationship between the increments and the readings of the counting block has become simpler) and this dependence is straightforward.

Claims (2)

Thus, the proposed device eliminates the influence of the heterodyne on the measurement result, reduces the warm-up time of the device, simplifies the calculation formula for determining the desired DRS and ultimately improves the instrumental accuracy of the device and simplifies the operation of the device. Claims a near frequency comparator comprising a series-connected measured frequency unit, a mixer, a frequency divider and a counting unit, serially connected multiplier and counting pulse generator, the output of which is connected to the second input of the counting unit, characterized in that measurements, the first additional frequency divider and an additional mixer, the second additional divider, the output of which is connected to the input m of the first additional frequency divider and the second. the mixer input, wherein the output of the additional frequency mixer is connected to the input of the channel of the measured frequency, and the second input of the additional mixer is connected to the input of the second additional divider, the input of the multiplier and the second input of the counting pulse generator. Sources of information taken into account in the examination: 1. The author's certificate of the USSR 318870, cl. G, 01 TR 23/02, 07.19.70. 2. USSR author's certificate 413431, cl, & 01 T 23/00, 3.04,72.