SU868610A1 - Frequency meter - Google Patents

Description

one

The invention relates to a measurement technique, namely to frequency meters and can be used in radio engineering equipment for various purposes for measuring frequency, duration and number of pulses.

Known frequency meters containing generators, triggers, selectors, arithmetic units and indicators GI.

A disadvantage of the known devices is low measurement accuracy.

Of the known electron-counting frequency meters, the closest in technical essence is a frequency meter containing a crystal oscillator, the output of which is connected to the input of frequency dividers, the counting unit, whose counting input is connected to the output of the selector, and the output - having discrete elements G23.

The disadvantage of this device is that the measurement of the frequency and continuous counting of the impulse is carried out on one input, and the measurement of the duration on the other, which requires additional switching on the instrument and on the object under study and reduces the reliability of the device.

The purpose of the invention is to increase the reliability of the device.

This goal is achieved by the fact that in a frequency meter containing a series-connected crystal oscillator and a frequency divider, as well as a selectr, whose output is connected to the first input of the block counter, the output of the latter is connected to the input

10 blocks of indix, entered in series the first, second elements 2 AND-NOT, the first element 3 AND-NOT, the third and fourth elements 2 AND-NOT, as well as the RS flip-flop, the second

15 element 3 AND-NOT, fifth and sixth elements 2 AND-NOT and two keys, the output of the first of which is connected to the first input of the RS flip-flop. and to the first input of the p element 2 AND-NOT, the second input

20 which is connected to the output of the first element 3 AND-NOT, while the output of the second key is connected to the second input of the RS flip-flop, to the first input of the second element 3 AND-NOT and to the second

25 input of the first element 3 AND-NOT, the first input of which is connected to the first input of the selector, with the second input of the counting unit and with the second input of the fourth element 2 AND-NOT, output

30 last connected to the second input

the third element 2 AND-NOT and to the third input of the first element 3 AND-NOT, the first output of the RS-flip-flop is connected to the second input of the second sjTfeMeHTa 3 AND-H and the first input of the sixth element 2 AND-NOT, the second input of which is connected to the second input the selector, the third input of the latter is connected to the output of the second element 3 AND-NOT, the third input of which is connected to the first output of the frequency divider, the second output of which is connected to the first input of the first element 2 AND-NOT, the second input of the last connected to the second input RS- trigger, the output of the sixth element 2 is NOT connected to the second the second input of the second element 2 is NOT, and the output of the second element 2 AND is NOT connected to the second input of the counting unit.

The drawing shows a block diagram of the frequency counter.

The frequency meter contains four elements 1-4 2 AND-NOT, element 5 3 AND-NOT, set of lecturer 6, display unit 7, counting unit 8, element 9 2 AND-NOT, RS flip-flop 10, element 11 3 AND-NOT, block 12 frequency divider, crystal oscillator 13, keys 14 and 15, element 16 2 AND-NOT

The device works as follows.

When the switching key 15 RS trigger 11 is set to a logical zero, which prohibits the passage of the signal of the crystal oscillator 13 from the divider unit 12, the frequency on the element 11.

The logical unit from the inverse output of the RS flip-flop 10 permits the signal to be processed from the block 12 of the frequency divider through element 1. After passing through element 2 of this signal, a short reset pulse is generated from the 4 and 3 elements removed from the element 5, so as a logical zero appears at the input of element 16, a single signal resets the counter of the counting unit 8, the selector b is allowed and the pulses from the frequency meter input pass to the counting input of the unit 8. At the end of the pulse 0.5 Hz from the output of the zero level element 2 m is prohibited from passing through signals from the input selector 6, is produced from census counter in memory in the counting unit 8 and is outputted to the display unit 7.

Since the reset signal is formed by a positive signal edge of 0.5 Hz (the duty cycle is 2), and the census signal is formed by its negative front, frequency measurement occurs every 2s.

During short-term switching of the key 14 and the inclusion of a continuous counting of pulses, the RS-tripiJepep 10 is set to a logical unit that permits the passage of pulses from the block of 12 frequency dividers

1 MHz to the selector 6 and prohibits the passage of 0.5 Hz pulses on element 1. Since resolution 9 enters element 9 from RS flip-flop, the resolution comes from the leading edge of the measured pulse after passing through elements 9 and 2, a reset pulse is generated elements 5, 4 and 3. From element 2, a positive impulse allows the operation of the selector 6 and to the I-count input of block 8 through the element

11 and the selector 6 receives 1 number of 1 MHz time stamps, depending on the duration of the measured pulse. At the end of this impulse, a census takes place from the counting memory.

s block 8.

When latching key 14, the signal from the 12 splitter unit of 0.5 Hz and 1 MHz is prohibited. The selector b is allowed and the input pulses are

0 are on the counting input of block 8.

Following each counting pulse, a census pulse is sent from element 2 to the census input of the counting unit 8 and from the meter to the memory of block 8

5 records a new number one greater than the previous one. The element 5 with the key 14 receives a logical zero, which prohibits the formation of reset pulses. From block 8

j, the information is transmitted to the indication unit 7.

Thus, a continuous pulse counting occurs.

The proposed frequency meter favorably differs from the known convenience of using it in workshop conditions, since it does not require the use of two inputs to measure the frequency and duration of the pulses. The absence of

0 in the circuit of discrete elements allows the frequency meter to be executed as a miniature probe in the form of a probe and provide it with a known indicator of logical states. Small dimensions of the instrument

 and ease of management ensures its location in hard-to-reach places, which speeds up the process of researching objects and reduces the costs of their commissioning.

Claims (2)

Invention Formula A frequency meter containing a series-connected crystal oscillator and a frequency divider, as well as a selector, the output of which is connected to the first input of the counting unit, the output of the latter is connected to the input of the display unit, characterized in that, in order to increase reliability, the first, second elements 2 AND-NOT, the first element 3 AND-NOT, the third and fourth elements 2 AND-NOT, as well as RS-trigger, the second element 3 AND-NOT, fifth and sixth elements 2 AND-NOT and two keys, the output of the first of which is connected to the first input of the RS flip-flop and to the first input of the fifth element 2 AND-NOT, the second input of which is connected to the output of the first element 3 AND-NOT, while the output of the second key is connected to the second input of the RS flip-flop, to the first input of the second element 3 AND-NOT and to the second input of the first element 3 AND-NOT, the first input of which is connected to the first input of the selector, with the second input counting unit and with the second input of the fourth element 2 AND-NOT, the output of the latter is connected to the second input the third element 2 AND-NOT and the third input of the first element 3 AND-NOT, the first output of the RS-flip-flop is connected to the second input of the second element 3 AND-NOT and the first input of the sixth element 2 AND-NOT, the second input of which is connected to the second input selector, the third input of the latter is connected to the output of the second element 3 AND-NOT, the third input of which is connected to the first output of the divider frequency, the second output of which is connected to the first input of the first element 2 AND-NOT, the second input of the last connected to the second output RS- trigger, the output of the sixth element 2 AND-NOT connect n with a second input vtorEhm 0 of the element 2 is AND-NOT, and the output of the second element 2 of the AND-NOT is connected to the second input of the counting unit. Sources of information taken into account in the examination 1, USSR Author's Certificate No. 618854, cl. H 03 K 23/01, 1978. 2. Frequency meters electronic electronic invoices universal small-sized, catalog-project. Radio measuring instruments. 78, ed. ekoe.