SU439766A1 - Device for phase meter calibration - Google Patents

Description

one

The invention relates to a phase-measuring technique.

A device for checking high-frequency phase meters is known, which contains a reference frequency block, a frequency synthesis block, automatic phase adjustment nodes, two identical channels, in each of which a wideband amplifier, attenuator, capacitive voltage divider, mixer, limiter, pulse-phase amplifier are sequentially included. detector, phase-determining and phase-measuring nodes.

However, the known device is complex: but constructive, it cannot work in the range of low and infra-low frequencies and has a relatively rare frequency step.

To expand the frequency range and reduce the frequency step, the proposed device is equipped with a circuit consisting of two mixers-dividers in series, two filter mixers, and a low-pass filter mixer that acts as a local oscillator, with two identical channels, each of which includes two mixer filters and a mixer with a low-pass filter connected to the input of a broadband amplifier, the inputs of the first filter mixers are connected to the outputs of the automatic phase adjustment nodes, and ry inputs of the filter mixers and

the inputs of the mixer-dividers are connected to the corresponding outputs of the reference frequency block, the second inputs of the second mixer-filters are connected to one of the inputs of the block

frequency synthesis, and the second inputs of the mixers through the electronic switch of the frequency synthesis unit are connected to the outputs of the reference frequency block, the outputs of the pulse-phase detector through the switch contacts are connected to

inputs of nodes automatic phase adjustment.

In addition, in order to provide a coptrol for the frequency of the output signal of the installation and to measure the frequency of an external source, a high-frequency connector connected to the phase-measuring device is inserted into the device.

The drawing shows a block diagram of the described device, consisting of a two-phase generator and a digital phase-measuring device.

The flowchart includes the following

elements: pulse phase detectors 1,2,

phase setting device 3, phase measuring device 4, mixers-filters 5-10,

limiting amplifiers 11-13, nodes 14, 15 of automatic phase adjustment, mixer 16, 17, mixers 18-23, capacitive voltage dividers 24, 25, attenuators 26, 27, wideband amplifiers 28, 29, matching stage 30, high-frequency connectors

31, 32, 33, toggle switch 34, frequency synthesis block 35, reference frequency block 36.

The principle of operation of the device is as follows.

In block 36 of the reference frequencies from a highly stable oscillator, a number of spectrally pure signals are generated, for example, from 30 to 39 MHz in 1 MHz steps. from 3.0 to 3.9 MHz, with steps of 100 KHZ, as well as several auxiliary signals.

In block 36, signals of a frequency of 3.1 MHz and a frequency of 33 MHz are paired up at the inputs of the mixer separator 17, where the differential beat frequency of 29.9 MHz is separated by selective amplifiers and divided by a decadal frequency divider 10 times.

The output signal of the mixer-separator 17 with a frequency of 2.99 MHz is supplied to NU one of the inputs of the similar mixer-separator 16, and a signal with a frequency of 33 MHz is applied to the second input of which.

After separating the difference beat frequency and dividing the decade frequency divider at the input of the mixer divider 16, a signal with a frequency of 399 kHz is generated, which then enters the input of the mixer node of the filter 6 A signal with a frequency of 3 MHz from block 36 is fed to the first inputs of nodes 14 and 15 and the second inputs which are driven through the toggle switch 34 control voltages from the pulse-phase detectors 1 and 2, the phase of the high-frequency signal of 3 MHz is shifted, which is then fed to the input of the mixer filter 5 (10). Selector systems of filter mixers 5, 10, and 6 isolate the total beat frequency. Thus, at the output of the mixer-filter 6 node, a signal with a frequency of 36.001 MHz will be generated, and at the outputs of the filter mixers 5 and 10 a signal with a frequency of 36 MHz. In the frequency synthesis block 35, by adding, subtracting, multiplying and dividing the signals of the block 36, a high frequency signal is generated in the frequency range 3-4 MHz.

The frequency of this signal depends on the position of the decade switches.

The output of the synthesis unit with a frequency of 39577823 Hz is fed to the inputs of the mixer filters 7, 8, 9, the total beat frequency is allocated, and the frequency of the signal at the output of the attenuator 26 is always 1 KHz higher than the output signals of the mixer filters 7 and 9. For example , for the above positions of the decoder switches, we obtain: at the output of node 7 — a signal with a frequency of 39577823 Hz, at the output of the attenuator 26 — a signal with a frequency of 39578823 Hz, at the output of the node 9 — a signal with a frequency of 39577823 Hz.

The output signals of nodes 7, 8 and 9 are fed to the inputs of mixers 19, 20 and 21, respectively, and to the second inputs of these mixers one of the signals from unit 36 with a frequency of 30-39 MHz is passed through in 1 MHz steps.

The differential beat frequency is allocated by a low pass filter. The output signal of the mixer 19 (21) through the wideband amplifier 28 (29) and attenuator 26 (27) is connected to the output high-frequency connectors 31 (32) of the two-phase generator.

The output voltage of the mixer 20, which functions as the local oscillator, is fed to the inputs of the mixers 18 and 22, and the second inputs of these machines through capacitive voltage dividers 24 and 25 are connected to the output connectors 31 and 32 of the two-phase generator. If, when changing the output voltage with the help of a step attenuator, we simultaneously switch the capacitance of capacitive voltage dividers 24 and 25 so that the product of the attenuation coefficient of attenuators 26 (27) and the attenuation coefficient of voltage dividers 24 (25) is approximately constant. m, the amplitude-phase error in a two-phase generator will be insignificant.

The signal of the difference beat frequency 1 kHz is amplified by a servo-type limiting amplifier and is fed to the input of the pulse phase detector 1 (2).

If the heterodyne signals to the mixers 18 and 22 are in-phase, which is easy to achieve by selecting the length of the connecting cables, then the converted signals of the difference beat frequency will have the same phase shift as the output high-frequency signals.

From block 36, a 3.6 MHz signal is applied to the input of the phase generating unit 3, the output of which produces two sequences of pulses, for example, the frequency

1 KHZ.

Using pulses node 3 continuously

Pulse-phase detectors 1 and 2 are polled, at the inputs of which are trapezoidal pulses of limiting amplifiers 11 and 12, respectively.

The output signal of the detector 1 (2) through

the contacts of the toggle switch 34 acts on the control input of the node 14 (15), which has an electronic and electromechanical phase adjustment, and will until then change the phase of the oscillating signal with a frequency of 3 MHz, while between

the output high-frequency signals will not establish a phase shift equal to the phase mismatch established in the phase-setting unit of the device 3.

Phase shift introduced by my attenuator

a wideband amplifier and load connection, is worked out by systems of automatic phase adjustment.

When the device operates in the low and infra-low frequency range, the automatic phase adjustment system is turned off using the toggle switch contacts 34.

Subject invention

Claims (2)

1. Device for checking phase meters, containing a block of reference frequencies, inputs connected to the same outputs of the frequency synthesis unit, two identical channels, each of which includes a broadband amplifier, an attenuator, a capacitive voltage divider, a mixer, a limiter amplifier, a pulse-phase detector and an automatic phase adjustment node, as well as a low-frequency phase-matching node, each one input connected to one of the outputs of the reference frequency block and to the input of a phase-measuring node, and the other inputs connected to the outputs of limiting amplifiers of both channels and to the output of a single-channel A phase meter, consisting of a series-connected matching stage, a mixer and a limiter amplifier, the output connectors in each channel are connected between the attenuator output and the mechanically connected capacitive voltage divider, in order to extend the frequency range and reduce the frequency step, it is equipped with a device of two series-mixers-dividers, two mixer-filters and mixers with a low-pass filter in series, acting as a local oscillator, as well as two identical channels, each of which sequentially includes two mixers of the filter and a mixer with a low-pass filter connected to the input of a wideband amplifier, and the inputs of the first mixer filters are connected to the outputs of the automatic phase adjustment nodes, and the second inputs of the mixers are filters and inputs of mixer-dividers are connected with the corresponding outputs of the reference frequency block, the second inputs of the second mixer-filters are connected to ol, -, from the input of the frequency synthesis block, and The blender inputs of the mixer through the electronic switch of the frequency synthesis unit are connected to the outputs of the reference frequency block, the outputs and: the flash-phase detector through the switch contacts are connected to the inputs of the automatic phase adjustment nodes. 2. The device according to claim 1, characterized in that, in order to control the frequency of the output signal of the installation and to measure the frequency of the external source, it is provided with a high-frequency connector connected to the phase-measuring unit.