SU759972A1 - Device for measuring panoramic radio receiver input signal frequency - Google Patents

Description

The invention relates to a radio measuring technique and can be used in panoramic receiving devices and frequency meters.

A device is known for measuring the input signal frequency 5 of a panoramic radio receiver, which contains series-connected marker resonators, an amplifier, a tag generator and an electron-beam indicator, as well as a synchronization unit connected to the second input of the indicator, while the inputs of the marker local oscillator, . the input of the synchronization unit is connected to (5 output of the oscillator sweep generator, and the third input of the indicator is connected to the output of the receiver [1].

The drawback of the device is that the measurement of the frequency of the input-20 signal is accompanied by manual operations to determine the position of the response on the indicator sweep. At the same time, it is difficult to use automatic registration devices 25 and data processing. ~

It’s also a device for measuring the frequency of a panoramic signal

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frequency, mixer, narrowband filter with a detector, controlled key and pulse counter with a reset shaper, as well as a unit comparing the instantaneous frequency with a standard, whose input is connected to the second input of the mixer, the output to the first control input of the key, while the second control input of the key associated with the output of the receiver, the second input of the mixer - with the output of a tunable local oscillator, and the driver of the counter reset signal - with the output of the receiver tuning device. In the process of rebuilding the receiver's local oscillator, a sequence of pulses is generated from the output of the narrow-band filter; beats; an instantaneous frequency of the heterodyne with reference frequencies. The number of pulses received in the counter

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A disadvantage of this device is the low accuracy of the measurement of the frequency of the input signal, especially when the receiver oscillator is nonlinearly tuned, since the minimum step of the pulse train is about 759972

zovennyh beats instantaneous frequency of the local oscillator with the reference frequency,, is limited to the dynamic bandwidth of the narrowband filter. Therefore, to obtain time-separated pulses at the output of a narrow-band filter, it is necessary to use a grid of reference frequencies with a large pitch, which leads to low measurement accuracy. It is also necessary to note the difficulty of obtaining a small step of the reference frequency grid, especially in the microwave range.

The purpose of the invention is to improve the measurement accuracy.

This goal is achieved by the fact that the device for measuring the frequency of the input signal of the panoramic radio receiver containing serially connected reference frequency generator, mixer, narrowband filter with detector, as well as a key, the first input of which is connected to the second input of the mixer through the comparator, and the output is connected to the first input of the pulse counter, the second input of which is connected to the output of the reset signal shaper, is entered in series with a stepped voltage driver · with an integrator, the subtraction unit and the controlled pulse generator, while the output of the narrow-band filter with the detector is connected to the input of a stepped voltage shaper with. Tegrator, the output of the controlled pulse generator is connected to the second key input.

FIG. 1 shows a block diagram of a device for measuring the frequency of the input signal of a panoramic radio receiver; in fig. 2 - timing charts of the device.

A device for measuring the frequency of the input signal of the panoramic radio receiver contains a reference frequency generator 1, and a mixer 2, a narrowband filter Z. with a detector, a comparator unit 4, a step voltage driver 5 with an integrator, a Subtraction unit 6, a controlled pulse generator 7, a key 8, a counter. <9 pulses and shaper 10 reset signal.

The device works as follows.

The signal of the instantaneous frequency of the local oscillator of the receiver (Fig.2A) is fed to the inputs of the block 4 and the mixer 2. The block 4 generates a pulse (Fig.26) opening key 8 for the time of restructuring the heterodyne of the receiver.

'At the output of mixer 2, as a result of the interaction of the frequency of the local oscillator with a grid of reference frequencies (, ί, generator 1, a sequence of radio pulses is formed. Detected and normalized by

the amplitude of the pulses (figv), the time intervals between which are determined by the steepness of the modulation characteristics and the speed of tuning the local oscillator of the receiver, from the output of the detector narrowband filter 3 is fed to the input of the stepper 5, voltage with the integrator. In the imaging unit 5, the pulse sequence is converted into a step-shaped signal (FIG. 2d) “which is an approximation of the modulation characteristics of the local oscillator of the receiver, and is integrated by the integrator (FIG. 2d is a dotted line). From the output of the integrator of the driver 5, the signal is fed to the input of the subtraction unit 6, where, as a result of comparison with the signal of the oscillator sweep generator, a differential voltage (fig.2d) is formed that carries information about the nonlinearity of the receiver local oscillator. Differential voltage (error signal) from the output of block 6 controls the frequency of the generator 7 pulses. With an appropriate choice of the regulating characteristic of the generator 7 and the transmission coefficient of the block 6, each next pulse from the output of the generator 7 is produced when the local oscillator is tuned to equal frequency intervals, significantly less than the frequency grid step of the reference frequency generator 1. The pulse sequence from the output of the generator 7 through the key 8 is fed to the input of the pulse counter 9 (php.2e. At the time of tuning the receiver, the signal from its output receives a pulse closing the key 8 to pass a sequence of pulses to the input of the counter 9. The key 8 is open the time interval corresponding to the local oscillator rearrangement from the initial frequency equal to the frequency of the reference to the frequency corresponding to the receiver's signal setting. The counter 9 reading the number of pulses of the controlled oscillator 7 determines the frequency Igna.

At the end of the full cycle of receiver tuning, a command is sent to the reset signal shaper 10, as a result of which the counter 9 is transferred to its initial state.

Claims (1)

Claim Device For measuring the frequency of the input signal of a panoramic radio receiver, containing a series-connected reference frequency generator, a mixer, a narrowband filter with a detector, as well as a key, the first input of which is connected to the second input of the mixer, and the output of the key, the second the entrance of which is connected to the exit of formiro 759972 A reset signal is distinguished by the fact that, in order to increase the accuracy of the measurement, it has been entered consistently! connected stepwise voltage driver with integrator, subtraction unit and controlled pulse generator, while the output of the narrowband filter with detector is connected to the input of step voltage driver with the integrator, controlled output pulse generator connected to the second input key.