SU769462A1 - Device for calibrating high-frequency signal levels - Google Patents

Description

and the output — with one of the inputs of the corresponding strobe converter; The first input of the switch is connected to another input of the adder, and the second output through the first frequency multiplier is connected to one of the indicator inputs, the output of the adder is connected to another indicator input through the second frequency multiplier, and the output of the reference generator is connected to another input of the phase detector.

The drawing shows a functional diagram of the proposed device for calibrating the levels of high-frequency signals.

The device includes a reference generator /, an adjusting voltage divider .2, an exemplary voltmeter 3, attenuators 4, 5, strobe transformers 6, 7, / strobe pulse former 8, 9, tunable generator 0, DC amplifier J1, f, il low pass 12, phase detector 13, low frequency reference oscillator 14, intermediate frequency filters 15, 16, intermediate frequency voltage divider; / 7, phase shifter 18, voltage regulator (intermediate frequency level) 19, voltage divider (stabilized ary frequency) 20, a switch 21, an adder 22, umnozh1iteli frequencies 23, 24 and indicator 25.

The device works as follows.

The signal from the output of the generator / is fed to the input of the adjusting divider of voltage 2. With a minimum attenuator (s) of the voltage divider on its input, which is. is the output of the device; with the help of the reference voltmeter 3, the maximum output level — voltage f / max — is set. As is well known, in this case, the reference voltmeter B measures the highest harmonic signal and has a high accuracy of measurements, since the nonlinearity of the characteristic of the AC converter the marriage is practically unaffected. After that, with the help of an intermediate frequency voltage divider 17 on the indicator 25, a voltage equal to and max. The sample voltmeter 5 is intended only for setting / AAC and is not involved in further operations.

OtcqeT of attenuation introduced by voltage divider 2 at decreasing t / MOKs, is carried out by an intermediate signal at the output of the converter 6. their input signals to low intermediate frequencies. One of the channels of the device is a reference. It includes the stabilization of the frequency of the following pulses of the formers 8, 9, and therefore, the intermediate frequency is stabilized from the output of the strobe transducers 6, 7. The intermediate frequency is stabilized using a system containing the phase detector 13, ororoidal generator 14, f, and lower frequency 12, DC amplifier //, tunable generator / 0. The stability of the intermediate frequency is determined by the stability of the reference oscillator 14, which is made of quartz crystal.

Application of strobe converters 6, 7

allows you to eliminate the error in the indications of the model and calibrated voltmeters that occurs when the parasitic signal of the local oscillator passes to the input of the converter. Strp pulses passed on the trigger

the device does not affect the indications of the reference and calibrated voltmeters, since the frequency of the strobe pulses is much smaller than the frequency of the output signal, and their duration tends to

to zero.

Further, the output voltage of the strobe converter 6 through the intermediate frequency filter 15 and the voltage divider 17 is divided into two paths, and in one

of these, it is shifted in phase by an angle with the help of a phase shifter 18 and stabilized by a stabilizer 19. Thus, the voltage at the output of the stabilizer is stable in amplitude and shifted by 90 ° in phase. The signal from the output of the strobe converter 6 varies in proportion to the change in its input voltage. The voltages from the output of the intermediate frequency filter 15 and the stabilizer 19 are ultimately added up in the adder 22. The output voltage of the adder through the frequency multiplier 24 is fed to one of

the indicator inputs 25, and the second input through the divider 20, the switch 21 and the multiplier 23 is supplied from the voltage stabilizer 19. The indicator 25 measures the phase difference between the incoming signals

.Der

and performs the operations tgvr-, where Af is the change in the phase shift when the output voltage of the devices changes, and Lf is the multiplier of multipliers 25, 24.

Voltage divider 20 and switch 2 / allow discrete change of the value of stabilized levels at the input of adder 22 at low voltages at the output of the device. Increase: coefficient

L can reduce the calibration error by increasing the accuracy of phase measurements.

Claims (2)

Invention Formula A device for calibrating high-frequency signal levels, containing a reference oscillator, the output of which is connected to the input of one of two attenuators, a series-connected phase detector, a HI LOW frequency filter and a tunable oscillator, two intermediate frequency filters, the output of the first of which is connected to one of the inputs of the phase detector , reference frequency generator, phase shifter, summator, indicator and reference voltmeter, characterized in that, in order to improve calibration accuracy in a wide dynamic range In the frequency range, three voltage dividers, two strobe pullers, two strobe converters, two frequency multipliers, a voltage regulator and a switch are entered into it, the first voltage divider is set between the output of the reference generator and the inputs of another attenuator and a reference voltmeter, the second voltage divider between the output of the second frequency filter and the input of the phase shifter, and the third voltage divider between the output of the voltage regulator and the input of the switch, each input tors, pulses, connected to the output of the tunable oscillator, and an output - to one of inputs corresponding strobpreobrazovatel, strrbpreobrazovateley other inputs connected to the outputs of attenuators, and outputs - to the intermediate frequency filter inputs, the voltage regulator input is connected to the output of the phase shifter, whose input is connected to one of the inputs of the adder, the first output of the switch is connected to the other input of the adder, and the second output through the first frequency multiplier with one of the indicator inputs, the output of the adder through the second frequency multiplier connected to another input of the indicator, and the output of the reference generator is connected to the other input of the phase detector. Sources of information taken into account in the examination: . 1. Valitov R.A. Radiotechnical measurements, M., “Owls. radio, 1963, p. 271. 2. USSR author's certificate N ° 529423, cl. G 01 R 19/00, 1975 (prototype .ip). I M M t