SU954885A1 - Device for measuring frequency - Google Patents

Description

one

The invention relates to a measurement technique and can be used to measure changes in the frequency of electrical oscillations.

A frequency meter consisting of a meter connected in a ring, an integrator, a voltage-to-frequency converter, a adder and a key is known, the second input of the adder is connected to a reference frequency generator, as well as a driver, the inputs of which are connected to the starting device and the device input, and the output is with control input key G1. However, this device does not allow to measure the change in frequency with an arbitrary initial value.

Closest to the invention is a device for measuring the frequency increment, consisting of a series-connected reference frequency generator, control unit, key and counter, as well as an additional counter, overrun circuit, switch, and digital indicator 2.

However, this device allows the difference between the initial frequency R and the measured frequency Fn to be indicated only when, since the result is indicated, where FO -. upper limit measured by the meter capacity. In addition, the displayed result does not allow unambiguous determination of the frequency change. For example, with a measurement time of 1 s, the capacitance of the meters 10 and Hz is indicated on the scoreboard 250. This can be either with ff ' 1150 Hz (i.e., Hz) or with F2. 150 Hz (i.e. F "Hz).

 The purpose of the invention is to expand the functionality of the device for measuring the change in frequency by providing a measurement of any relationship between the original and the measured frequency.

This goal is achieved in that a device for measuring the frequency change, containing a series-connected reference frequency generator, a control unit, a key and a counter, has a digital indicator, the inputs of which are connected to the corresponding outputs of the counter, as well as a first switch, the input of which is connected to the second output of the control unit , and the outputs of the first switch, respectively, with the input of the zero setting and the write input of the counter, the input of the device connected to the second input of the key, additionally introduced soy The second trigger and indicator, the second switch in series and the register, as well as the third switch, whose input is connected to the trigger output, and the third switch output are connected to the counter's reverse input, the last overflow output is connected to the first trigger input, the second input of which is connected with the second output of the control unit, the third output of the latter is connected to the input of the second switch, the outputs and the setup inputs of the register are connected to the corresponding inputs and outputs of the counter. The drawing shows a block diagram of a device for measuring frequency. The device contains a reference frequency generator 1 connected in series, control block 2, key 3, counter k, trigger 5 and indicator 6 characters, as well as switch 7, register 8, switch 9 digital indicator 10, switch 11. It should be noted that unit 2 control is a circuit that forms a measuring interval during which the signal at its first output appears, as well as those delayed relative to the end of the measuring interval, one of which (with a lower delay) enters the third output of block 2, and the second - to the second exit b lock 2 controls The device works in four modes. 1. Memory mode of the original RJ frequency. The operating mode switches 7, 9 and 11 are in the first position. The second output of the control unit 2 is connected to the installation input of the zero count.

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ka, and the signal is not input to the reverse, which corresponds to the operation of counter 4 in the summation mode. In this position, the initial frequency F is measured during the measuring interval formed in the control unit 2 from the signal of the reference frequency generator 1, the key 3 is opened and the pulses are counted with the frequency F in counter A. After the measuring interval ends, the key 3 closes and the state counter k with the help of the signal of the third output of control unit 2 passing through the closed second switch 11 is rewritten into register 8. Digital indicator 10 indicates the value of F. Before each new measuring interval The resetting of the counter C by the signal from the second output of the control unit 2, 2 is exhausted. 2. The mode of measuring the change in frequency. The measurement of the frequency change is made at the second position of the switches 7, 9 and 11. In this case, before each measuring interval, the counter t is set to the state recorded in register 8, i.e. in the state corresponding to F, the same signal triggers 5 to such a state that the signal from its output through switch 9 puts the counter k into subtraction mode. During the measuring interval, the counter t receives pulses with a measured frequency f, and at the end: it, the state of the counter k, if F, F, the difference of frequencies, is measured in the same way as in the prototype. If F (, then in the counting process, the counter k reaches the zero state, and the overflow pulse from it overturns the trigger 5 .. which in turn will transfer the counter j to the adding mode. At the same time, the 6-digit indicator is activated. In the adding mode, the counter k is filled pulses with a frequency Fn for the time remaining until the end of the measuring interval, after which a state will be recorded in it, which characterizes, in the measurement mode of changing the frequency, the signal recorded in register 8 from the third output of the control unit 2 is not applied, since the second ne eklyuchatel 11 is open.

Thus, after the expiration of the measuring interval on 1 digital indicator 10 there will be information about the Fx difference module, and the sign indicator will show the sign of the frequency change.

3. The mode of measuring the frequency F while maintaining the recorded value of F.

In this mode, switches 7 and 9 are in the first position, and 11 in the second, i.e. From the third output of the control unit 2, the signal to the input of the register record 8 is not supplied. At the same time, the value of the measured frequency Fn is indicated on the digital display 10, and the register corresponding to the initial frequency value is stored in the register 8.

C. The mode of measuring the sum of frequencies F and F.

In this mode, switch 9 is in the first position, and switches 7 and 11 are in the second position. Before each measuring interval in the counter C from register 8 a frequency code F ,, is recorded. After the expiration of the measuring interval, the counter state k corresponds to the sum of the frequencies. In the case of an overflow of the counter h, as in mode 3, the indicator of the sign 6 is triggered, indicating that.

The use of new elements of the register, the trigger, the indicator of the sign and the second and third switches as well as the connections between them favorably distinguishes the proposed device from the prototype, since it allows uF to be measured with an arbitrary sign of the difference. eliminates the ambiguity of the measurement result, and can also operate in the frequency measurement mode F (i, preserving the recorded

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F values and in the mode of measuring the sum F + Fg ,.

Claims (2)

1. USSR Author's Certificate No. 530260, cl. G 01 R 23/00. 2. USSR author's certificate N, cl. G 01 R 23/00 (prototype).