SU374549A1 - ALL-UNION 'mmm ^ j ^ mrirmu - Google Patents

Description

one

The invention relates to the field of measurement technology and can be used in determining the average value of a parameter, expressed in frequency form, for the required length of time.

Known frequency meters containing the counting circuit and the clock pulse generator.

The aim of the invention is to provide an automatic installation when the averaging interval is changed.

For this purpose, a capacitor frequency converter and a digital-analog converter are introduced into the frequency meter. The output of the counting circuit is connected to a digital-analog converter, the control input of which is connected to the output of a capacitor frequency converter connected by an input to a clock pulse generator.

The drawing shows a diagram of the frequency meter.

The input of the shift register 1, consisting of series-connected cells with two stable states, is connected to the circuit 2 of the measured frequency, and the outputs Each of the cells of register 1 is connected to the contactless keys 3 of the register state converter /. The circuit of the series-connected resistors 4, which are part of the converter, is ground by the keys 3. A chain 5 of the forward (clock) pulses of the register / and the input of the stabilization unit of the conversion scale are connected to the generator 6 of pulses. A conversion scale stabilization node, made in the form of a capacitor frequency converter with a pulse feedback, consists of a trigger 7, a dosing unit containing a switch on the transistor 8 and a resistor I, a metering capacitor 10, diodes // and 12, a pulse circuit 13

feedback with the Zener diode 14. To the output of the stabilization unit connected a series of series-connected resistors 4, the indicator 15 and the circuit 16 of the electrical output signal.

When a shift register arrives at the input / through circuit 2 of a sequence of electrical pulses, the number of which reflects the measured frequency per unit of time, each pulse is recorded in the first cell of register 1 and successively transferred to subsequent cells at a speed proportional to the frequency of the advancing pulses fed through circuit 5 from the generator 6 pulses. Total advance time of each

pulse along register 1 is directly proportional to the number of register cells and inversely proportional to the frequency of the advancing pulses. The density (density) of the pulses recorded in these cells characterizes the degree of irregularity of their frequency during the progress along the register. At a constant frequency of the advancing pulses, the number of pulses recorded in the register / is proportional to the average value of the measured frequency during the averaging interval, equal to the time the pulse moves along the register /, the quotient from dividing the number of cells by the frequency of the advancing pulses. To convert the number of pulses recorded in the register into an analog electrical signal, the outputs of each cell are controlled by contactless keys 3. The number of non-shunted keys 3 resistors 4 and, therefore, the voltage drop across the entire series of series-connected resistors 4 (at a constant current converter circuit) is also proportional to the average frequency of incoming register / pulses at the averaging interval.

The scale of the transformation is stabilized by the stabilization unit by multiplying the voltage drop across the circuits of series-connected resistors 4 by an amount proportional to the frequency of the advancing pulses. This is due to the fact that the circuit of resistors 4 is powered by the output current of the stabilization converter capacitor converter. When a pushing-in trigger pulse 7 arrives from the pulse generator 6, the transistor 8 is closed and the metering capacitor 10 is charged until the stabilization voltage of the Zener diode 14 is applied.

In this case, a metered charge enters the circuit of series-connected resistors 4.

During the breakdown of the Zener diode 14 trigger 7

is transferred by a pulse arriving along the circuit 13, as a result of which the transistor 5 is unlocked and the metering capacitor 10 is discharged. Since the average value of the output current of the capacitor converter of the stabilization unit at a constant metered charge is directly proportional to the frequency of the recharge of the capacitor 10, the output voltage of the converter removed, for example, from circuit 16 or input

the indicator 15 is proportional to the average value of the measured frequency, regardless of the averaging interval specified by the frequency of the advancing pulses.

Subject invention

A frequency meter containing a counting circuit and a clock pulse generator, characterized in that a capacitor frequency converter and a digital-to-digital converter are introduced for the purpose of automatic installation when changing the averaging interval, while the output of the digital circuit is connected to a digital-analog converter, the control input of which connected to the output of a capacitor frequency converter connected by an input to a clock generator.