SU748269A1 - Shaper of measuring interval of digital frequency-period meter - Google Patents

Description

(54) FORMER OF MEASURING YNTER; YOAL DIGITAL FREQUENCY METER - PEMBDOMERA

I

. The invention relates to a digital measuring technique and can be used in digital often toomers - periodometers with automatic selection of the measurement limit.

A controlled frequency divider is known, which contains in each cell a counter, a trigger, an AND element, which requires additional equipment if it is used in the shaper of the measurement interval of the frequency meter l.

A device for forming a measurement interval is known, which contains a frequency divider, one output.

which through the OR circuit is connected to the single input of the first trigger {5a, and the other is connected to the synchronous input of the second trigger, the D input of which is connected to the inverse output of the first trigger, and each cell of the frequency divider contains a counting decade whose outputs are connected to the decoder inputs of the logical element unit and decoder zero l. .

Shy

  A disadvantage of the known device is the complexity of the frequency divider cells.

. "

The purpose of the invention is to simplify frequency divider cells.

This is achieved by the fact that, in the measurement interval former

5 digital frequency meter - a periodometer containing the first and second triggers, a frequency divider consisting of series-connected division cells with two inputs and outputs,

10 each of which contains a counting decade, the input of which is the first input of the cell, and the output - the first output of the cell, B-trigger, elements of OR OR, and the inputs of the first cell

5 are the driver input, the first output of the last cell is connected to a single input of the first trigger,; ia the second output of the last cell -: from the second trigger, D-in

20 of which is connected to the inverse output of the first trigger, the output of the second trigger is the output of the driver, in each cell of the division, the D-trigger synchronous input is connected to

25 to the input of the counting dexid, and the inverse output of the D-flip-flop is connected to the first input of the element I, the second input of which is the second input of the cell, the output of the element .and connected

30 cf by the first input of the OR element, whose second exit is connected to the output of the counting decade, the output of the LIE element is the second output of the cell.

The drawing shows the structure of the circuit shaper measuring interval.

Shaper contains a divider

Frequency 1, consisting of division cells -1 -1 - 2-n, each of which consists of a counting decade 3, B-trigger 4, the element OR 5 and the element AND 6, and also triggers 7 and 8.

In the initial state, the reset pulse from the frequency meter control device (not shown in the diagram) all the triggers and the frequency divider are set to the Zero state.

From the beginning of the measurement cycle, the control device supplies to the input 9 of the time generator the count pulses of the reference frequency (when measuring the frequency) or unknown (when measuring the period). The first impulse of the input frequency after the passage of a circuit consisting of elements b and 5 switches on the trigger 8 into a single state, which means the beginning of the strobe pulse of the measuring interval. The second input pulse passes to the output along the same circuit as the first (reference) pulse. Slice the second pulse trigger 4 first. The cells are set to one state, so that the element And b is closed until the end of the measurement cycle. After the arrival of ten pulses of the input frequency, the pulse from the output of the decade counter 3 passes to the output, and by its slice the trigger 4 switches to one state and closes the And b element in the second cell.

. Similarly, the 100th impulse from the output of the counter 3 of the second cell passes the shaper output.

The synchronous input of the trigger 8 receives impulses placed in time after the reference according to the law 104, where T is the period of the input frequency, g is the cell number.

When a pulse of the indication of the choice of the measurement limit is received, and the first pulse arrives at the most significant result counter of the result counter, the trigger 7 is turned into a single state. WITH

from this point in time, the D-input of trigger 8 is applied to a zero potential.

The dial and the closest impulse from the output of the divider turn off trigger 8. If there is no impulse of the limit sign, the pulse from the divider output turns on trigger 7 in one state and as a result trigger 8 switches.

Thus, the duration of the strobe pulse is always Q. ten and corresponds to the selected measurement limit. Compared to the prototype, simplification is achieved. frequency divider cells.

Claims (2)

Invention Formula The shaper of the measurement interval of the digital frequency meter is a periodometer containing the first and second triggers, a frequency divider consisting of series-connected dividing cells with two inputs and outputs, each of which contains a counting decade whose input is the first input of the cell, and 5 exit - the first exit of the cell, The L-trigger, the AND and OR elements, the inputs of the first Cell being the input of the former, the first output of the last cell is connected to the single input of the first trigger, and the second output of the last cell is connected to the synchronous input of the second trigger, D-input of which is connected to the inverse output of the first trigger , the output of the second trigger is a driver input, characterized in that, for the purpose of simplification, in each cell of the division of the frequency divider, the D-flip-flop synchronous input is connected to the input of the counting deck, and the inverse 0 D-flip-flop output connected to trans. the input of the AND element, the second input of which is the second input of the cell, the output of the AND element is connected to the first input of the OR element, the second The INPUT of which is connected to the output of the counting decade, the output of the OR element is the second output of the cell. Information sources,  taken into account during the examination 1. USSR author's certificate. No. 563728, cl .; H 03 K 23/24, 1977. 2. US Patent N 3729677, cl. 324-781), G 01 R 23/02, 1973.