SU608106A1 - Frequency deviation meter - Google Patents

Description

(54) FREQUENCY DEVIATION METER

moreover, the nhol of the selector. turntable gzloobbr. znogch) voltage is connected to the second output of the sawtooth generator generator, and the output of the reverse selector switch of the sawtooth voltage is connected to the second input of the counter.

The drawing shows a structural electrical circuit of the described meter.

The frequency deviation meter contains a high-frequency amplifier (UHF) 1, a mixer 2, an oscillator 3, a sawtooth voltage generator 4, a sawtooth voltage reverse selector 5, a gate 6, a counter 7, switch 8, an attenuator 9, a high-pass filter 10, a low-pass filter 11, a power comparison unit 12, an oryi 13. The measured signal is supplied to the input bus 4.

The principle of operation of the meter is as follows.

After powering on, the meter starts operating a voltage generator 4, the retrace pulses of which are extracted by the servo voltage reverse selector 5. Under the influence of the first reverse pulse, arriving at one of the control inputs of the switch 8, this switch connects the high-pass filter 10 to the mixer 2. Subsequently, the switch 8 remains in this position until its other control input receives a pulse from the null organ 13. As a result of this, at the beginning of the first measurement cycle, the spectrum of the studied FM signal falls into the passband of the high-pass filter 10. As more and more of the spectrum enters the passband of the high-pass filter 10, the power released by this filter increases. From its output, this power is supplied to the first input of the power comparison unit 12, to the second input of which the attenuator 9 is attenuated 9 times the power of the received FM signal. In this case, the attenuation of the attenuator 9 must be equal to 23 dB and, therefore, 0.5% of the FM signal power is supplied to the second input of the power comparison unit 12.

At the time when 0.5% of the total power of FM oscillations hits the passband of the high-pass filter 10, the powers of the signals at the first and second inputs of the power comparison unit 12 will be equal, to the null body 13 will fix this equality, issuing a corresponding impulse.

The zero-organ impulse 13 will open the valve 6, resulting in a counter. 7 counts the value of the frequency of the local oscillator 3 at a given time (. The same impulse received at the second control input of the switch 8 causes it to switch, causing the switch to connect the low-pass filter to the output of mixer 2. This is the first jBXOA comparison unit 12 power is supplied enamelno more power than on the second batch of this device.

With a further change in the frequency of the local oscillator 3, the spectrum of the studied FM signal gradually goes out of the passband of the low pass filter 11, and the power allocated by this filter will decrease. At that point in time, when 0.5% of the average FM signal power remains in the passband of this filter, the signal powers at both inputs of the power comparison unit 12 will again be equal, which will fix the null organ 13, giving a second pulse. This pulse arrives at the control input of the valve 6, opens it, as a result of which the counter 7 counts the second frequency value of the local oscillator 3 - Ij urr. When a second zero-body pulse 13 is applied to the second control input of the switch 8, the latter remains in the same position, i.e. Connects to the mixer 2 a low-pass filter 11 to the end of the measurement cycle. The measurement cycle ends at the moment when the ramp voltage of the generator 4 and the pulse retraction is completed, which is selected by the rake voltage selector 5 and fed to the first control input of the switch 8, causing it to switch. As a result of this, the switch 8 connects to the mixer 2 a high-pass filter 10. The reverse pulse also arrives at the counter 7, under the influence of which the counter deactivates the larger calculated value of the frequency and the smaller value fixes the difference obtained.

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as a measured frequency deviation value of a wideband FM signal. Further, the measurement cycle is repeated.

Claims (2)

Invention Formula A frequency deviation meter containing a mixer, one input of which through a high-frequency amplifier is connected to the input signal of the measured signal, the second input of the mixer is connected to the output of the local oscillator and the first input of the valve, the output of which is connected to the first input of the counter the switch, the second control input of which is connected to the second bentil input, the switch outputs are connected to the nerve input of the power comparison unit through the low and high frequency filters, the second input is The second attenuator is connected to the input of the switch and the output of the mixer, and the control input of the local oscillator is connected to the first output of the sawtooth generator, characterized in that, in order to reduce the measurement error, a selector is introduced into it. returning the sawtooth voltage to the null organ, whose input is connected to the output of the power srnngni unit, and the output of the null organ is connected to the second inputs of the valve and switch, and the selector input is connected to the second output of the pilo & voltage, and the output of the servo voltage reverse selector is connected to the second input of the meter. Sources of information taken into account in the examination:. US patent number 3909599. cl. 235,151 1) 30.09.75. 2. Rogovenko. Radio metering devices, 1974, p. 161.