SU752794A1 - Pulse recurrence rate to code converter - Google Patents

Description

one

The invention relates to the field of automation and computer technology and is intended to convert the frequency of pulses into a code with a conversion time equal to several periods of the frequency being converted.

Known frequency converters pulses in the code containing the counter, the valve of the reference frequency, the decoder reference points, the register and the linearization counter 1.

A disadvantage of the known devices is the low measurement accuracy.

The closest in technical terms to the invention is a device containing a pulse counter, a reference frequency valve, a reference point decoder, a shift register, a measured frequency valve, a time interval shaping unit, and a clapper and a reference frequency 2.

The disadvantage of this device is low measurement accuracy.

The purpose of the invention is new measurement accuracy.

This goal is achieved in that a device containing a shift register, a serially connected time interval forming unit, a reference frequency valve and a pulse counter are inserted into a clock pulse generator, a serially connected valve block and an accumulator adder, the second input of which is connected to the first output of the clock pulse generator , the second output of the latter is connected to the third input of the accumulating adder and to the first input of the shift register, the second input of which is connected to the output of the the second input of the latter is connected to the output of the pulse counter, the first input of the clock pulse clock is connected to the output of the timing module, and the second input of the clock pulse generator is connected to the second input of the reference frequency.

FIG. 1 shows a block diagram of the device; in fig. 2 - time diagram of the device.

The device for converting the frequency of the pulses into a code contains a block 1 for forming a time and a terminal, a clapai 2 of the reference frequency, a counter of 3 pulses, a valve block 4 accumulating the adder 5, a shift register 6 and a clock pulse former 7.

The device works as follows.

The time interval shaping unit 1 generates a time interval tn equal to n periods of the measured frequency during which the valve 2 of the reference frequency is open and the counter 3 pulses the reference frequency.

The shaper 7 at this time is blocked by the signal received by 1, and it is the input to the prohibition from the block 1 forming the time interval. After the end of the time interval tn on the counter 3 is recorded

N

proportional rate

at the measured frequency. Conversion code in the frequency code by the formula

NO

happens after graduation

d.

N

time interval / „as follows.

In the accumulating adder 5 is entered the code of the number L / o n / fl. Since the number, the sign bit of the accumulating adder 5 is in the unit state and the control input of the valve unit 4 is fed, the potential of the logical unit enters. Under the action of this potential, the valve block 4 inverts the L / t code from the output of the counter 3 and transmits this inverse code to the input of the accumulating adder 5. Next, the imaging unit 7 forms the first beat T1, resulting in the addition of the / Vo code in the accumulating adder 5 . After the end of the first clock cycle T1 in the accumulating adder 5, the number NI NO-yVx is recorded, which may be positive or negative. The relationship of the sign bit accumulating adder 5 with the lower register bit 6 is designed so that at the moment when the shaper 7 produces a T2 shift cycle, the sign bit of the accumulator adder 5 is recorded at the lower bit of register 6 contains their accumulator adder 5 and register 6 for one bit in the direction of the senior bits. This ends the first cycle of converting the code to the fx code, as a result of which in register 6 the value of the first most significant bit of the fx code is written.

After the first cycle in the accumulating adder 5, the number Ai is found. Depending on the sign of this number, either the potential of a logical unit or the potential of a logical zero enters the equalizing input of the valve unit 4. In the first case, the valve unit 4 inverts the code, in the second case, the direct code of the NT number is transmitted to the accumulating adder 5. After that, the former 7 generates the second two clock cycles T1 and T2, as a result of which the second bit of the fx code is generated and

and so on. The number of cycles of converting an LT code to an fx code is selected depending on the required conversion accuracy. Most often the number of cycles is equal to the number of bits in counter 3.

After the completion of all m cycles in register 6, the measured frequency code fx appears.

The conversion time of the LT code to the fx code is

 , A3T,

f

etc

/ floor

where Lat is the capacity of the counter 3.

The total time of conversion of pulses into a code / f is equal to

2

„+ Ch-7 +

log, N,

ti

/ floor

Jx

The error in converting the frequency of the pulses into a code is the sum of the error of the quantum dots and the error of converting the code VT to the code fx, and the last error can be reduced to almost zero by increasing the number of conversion cycles, while the number of bits of accumulating adder 5 and register 6 slightly increases.

Thus, in this device, the accuracy of converting the frequency of pulses to a code is actually determined only by the error of quantization of the time interval tn by frequency pulses / fl, at the time of frequency conversion to code close to the time interval.

Claims (2)

Invention Formula Frequency conversion device pulses into a code containing a shift register, a series-connected time interval forming unit, a reference frequency valve and a pulse counter, characterized in that to increase the accuracy of the conversion, a clock pulse former, successively connected valve block and accumulating adder, the second input of which is connected to the nerve, are entered into it the clock pulse generator output, the second output of the latter is connected to the third input of the accumulating adder and the first input of the shift register, the second input of which is connected to the output of the accumulating adder and the first input of the valve unit, the second input of the latter is connected to the output of the pulse counter, the first input the clock pulse generator is connected to the output of the time interval shaping unit, and the second clock pulse input is connected to the second valve input of the reference frequency. Information sources, taken into account in the examination of the USSR 1. Copyright certificate № 462283, cl. H OZK 13/20, 1973. the USSR 2. Copyright certificate D 373872, cl. H OZK 13/20, 1971. / X zg L - i II