SU394726A1 - DIGITAL FREQUENCY - Google Patents

Description

The invention relates to the field of electrical measuring equipment.

The known digital frequency meter, which contains a reference frequency generator, a reversible counter — a shift register, a result register, a range counter, a control device, a pulse shaper, triggers, inhibit circuits, an OR circuit, a shift register, and a shift number decoder, is characterized by a narrowed measuring range.

The proposed device differs from the known ones in that the output of the pulse generator is connected to the trigger input, the control inputs of the inhibit circuits, and through the inhibit circuit and the OR circuit to the reverse counter shift circuit, the second input of the OR circuit of the shift number decoder .

Such an embodiment of the device allows the measurement range to be expanded.

The drawing shows a block diagram of the described device, consisting of a reference frequency generator 1, a reversible counter — a shift register 2, a shift register 5 formed by triggers 4 and delay lines 5, a result register 6 formed by triggers 7, a count counter 8 9, triggers 10, 11, the driver 12 pulses, the scheme "OR 13, the decoder 14 the number of shifts and s.hem 15-21 of the ban.

The device works as follows. The base of the number system for the proposed scheme is 2.

The principle of operation of the device is based on the implementation of the dependency.

t

 :: i: Л, „; P .v t --- o

Where; Г „- time of measurement on the range;

7.V - period of following impulses of unknown frequency; L, n - number in t; raz de; P is the base of the number system; w is the number of bits that is determined by the required accuracy.

The measured frequency is F -,

K, one N i VVm; P is determined by the operation desh; about

which is carried out by the device.

By the command "Start operation", the control device 9 sets the circuit to the initial state, while the trigger 10 is set to "O" and the code defining the measurement time T in the first range is entered into counter 2.

With the arrival of a measured signal pulse, trigger 10 is thrown and from its "zero output" the unit is rewritten to the first trigger 4, and "single output opens circuit 15. Simultaneously, trigger 11 is set to the position where circuit 18 opens, and pulses from the generator output / arrive at the register input 2.

If during the time T no pulse arrives at the input of the driver 12, i.e. the first trigger 7 of register 6 is "zero", then the pulse from the output of register 2 passes through circuit 19 and goes to block 9 and counter 8. The device is set to initial the state, with the impulse from the output of block 9, the shift decoder has passed 14 and the OR 13 scheme will perform one code shift in register 2 in the direction of the higher bits. Measuring interval

at the same time 72 2G1 doubled.

With the arrival of the immersion at the input of the former 12, the operations are repeated. If during the time of Gs there is not a single pulse, then the iizo will have a doubling of the measurement interval. This is realized by double shifting the source code D register 2. The process of choosing the timing of measuring r continues until V, nerves / trigger) 7, is written "1. In this case, the range code is written to counter 8.

Thereafter, circuit 19 closes and, with the hectare 20, it opens. The trigger // and, M1I; the end of the measuring interval is thrown, the circuits 17, 16 open, the circuit 18 closes. Pa deducting input of register 2 will receive emulsions from the generator /. The pulse from the output of circuit 20 enters register 3 and shifts the unit on one bit and opens circuit 2 of the second bit of register 6. With a pulse input to the input of a shim: body 12, the trigger // is thrown, the pulse itself goes through circuit 21 . In register 2, at the time of arrival of the pulse, the reverse time code / o is obtained, which is obtained as a remainder by dividing the measurement interval T, pa 1 | Period of time to measure the T signal.

/ ;. -f / 0.

At the same time, the pulse passes through circuit 16 and shifts code ъ register 2 in the direction of higher bits, t, that is, code 2 / о is generated. The trigger // opens circuit 18 and code 24 is converted i; interval to-T ,, where is the period of the pulse generator. Interval 2 / and -7o is divided by pa, i.e., during this time the impulse will pass on the input of the driver 12, it will be written to trigger 7 a second time: row, while copying the measurement result information from a reversible trigger code 7 second bit After receiving the pulse from the output of register 2, the trigger 11 generates a code for the interval ti. The unit is shifted in register 3 and the code in register 2, i.e. a time interval of 27 ° / o is formed. Since double negation gives the initial value, in the third bit the result is removed from the direct trigger code 7.

Thus, the values of each of the t bits are formed, and in the even bits, the result is taken from the reverse number; 5. After forming the value of the ni bit, the sigal of the flip-flop 4 enters block 9 and the skgc slider is repeated.

PRED MET & A REFERENCE

A phytometer meter, a reference frequency generator, a reversible counter shift register, a result regimenter, a dPap0101 counter, a control device, a pulse driver, triggers, an inhibit circuit, an OR scheme, a shift register and a shift number decoder that, in order to extend the range measurement, i (the output of the pulse generator is connected to the trigger input, the control inputs of the inhibit bar and through the inhibit circuit and the OR circuit with the reverse counter shift circuit, and the second input of the OR circuit yield sdvigos number decoder.