SU375588A1 - ALL-UNION - Google Patents

Description

II

The invention relates to the field of electrical measuring equipment and can be used to improve the accuracy of measuring the average frequency of the passband of selective devices.

The known meter of the average frequency of the passband of the selective devices, which contains a panoramic meter of amplitude-frequency characteristics and an electron-counting frequency meter, has a low measurement accuracy.

The proposed meter is provided with a trigger circuit, a setup circuit and two pulse selectors connected in series to the channel for forming counted pulses and to the channel for forming the measurement time interval, the control inputs of which are connected to the output of the trigger circuit. The first input of the circuit is connected to the level setting circuit, and the second to the output channel of the vertical deflection of the panoramic meter, the input of which is connected to the frequency counter input.

Such an embodiment of the device improves its accuracy.

The drawing shows a block diagram of the meter.

The average frequency meter consists of a panoramic meter 1 frequency characteristics formed by the generator 2 kachayuodois frequency, detector 3, amplifier 4,. electron beam tube 5 and a sawtooth voltage generator 6; electron-countable frequency meter 7, which contains the pulse generator 8, the time selector 9, the counter 10 measured pulses, the generator 11 reference pulses, the time counter 12 and the control trigger 13; time selectors 14, 15, the trigger circuit 16 and the device 17 level setting.

The meter works as follows. The generator 6 generates a signal that periodically linearly changes the frequency of the generator 2 and, in phase with this change, realizes a horizontal scan on the screen of the tube 5. The variable frequency signal comes from generator 2 to the input of the selective device 18 and causes a frequency-modulated pulse at its output which, having passed the detector 3 and the amplifier 4, is fed to the vertical deflection plates of the tube 5 and draws on its screen an image of the amplitude-frequency characteristic of the device under study. This

5, the amplified video pulse passes to the trigger circuit 16, which produces a square pulse. The trigger level of the trigger circuit depends on the voltage supplied from the device 17 installation level0 n. Impulse at the output of the trigger circuit suI

It exists when the voltage at the output of amplifier 4 exceeds the voltage from device P. In order to visually set the required level with respect to the 1-frequency characteristic, the voltage from the output of device 17 is simultaneously supplied to tube 5. A rectangular signal of the trigger circuit with duration t opens the time selector 14, and the frequency from the output of the selective device, previously converted into an in-phase pulse sequence in the pulse shaper 8, through open selectors 14 and 5 is fed to the sc tchik 10 pulses. The pulse counter indicator shows the number of pulses that would arrive at it during the same time interval t when a constant frequency fcp is applied.

L {F (t} dt F ,, i, and Fcp

Since the interval t is usually much less than 1 sec. the meter counts N 1.Ni in seconds.

A rectangular impulse from the output of the trigger circuit 16 simultaneously with the temporary selector 14 opens the temporary selector 15, through which the pulses from the pulse generator, operating at the reference known frequency, pass. These impulses with

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the output of the selector is fed to a time counter 12, designed so that after the arrival of such a number of pulses from the generator 11, which corresponds to 1 sec / s, the counter overflows, and at its output appears a pulse acting on the flip-flop 13 and throwing it. The temporary selector 9 is closed, the counter 10 stops receiving pulses from the driver 8, and the digital display of the counter 10 shows the average frequency.

Subject invention

A mid-frequency bandwidth meter for selective devices, comprising a panoramic meter of amplitude-frequency characteristics and an electron-counting frequency meter, characterized in that

increase accuracy, it is provided with a trigger circuit, a level setting circuit and two glyuchnymi consistently in the channel forming the counted pulses and in the channel forming the measuring time interval time selectors, the control inputs of which are connected to the output of the trigger circuit, the first input of which is connected to the level setting circuit, and the second to the output channel of the vertical deflection of the panoramic meter, the input of which is connected to the input of the frequency meter.