Digital frequency meter

Digital frequency meter _simple and best laungage to learn and present_made by pure no copy from anysite_thank you!!!

1. Gandhinagar Institute of
Technology (012)
Prepared By :- Soham Gajjar
Branch :- Electrical Engineering
Div . :- B - 1
Active Learning Assignment
Subject :- Electrical Measurement and Measuring Instruments (2130903)
Enrollment no. :-
Topic :- Digital Frequency Meter

3. •The signal waveform is converted to trigger pulses
and applied contiously to an AND gate ,
• As shown …

4. * A pulse of 1 s is applied to other terminal,
and the number of the pulses counted during
this period indicates the frequency.

5. * The signal whose frequency is to be measured is
converted into a train pulses one pulses for each cycle of the
signal.
* The number of pulses occurring in a definite interval of
time is then counted by a electronic counter.
* Since each pulses represents the cycle of the unknown
signal the number of counts is a direct indicates of the
frequency of the unknown signal.
* Since electronic counters have a high speed of operation,
high frequency signals can be measured.

6. * The signal whose frequency is measured is first
amplified.
* The output of amplifier is applied to the Schmitt trigger.
(Block Diagram of Digital Frequency Meter)

7. Amplifier
* The signal whose frequency has to be measured is amplified by the
amplifier.
* This in necessary when the signal is weak.
Schmitt trigger
* The Schmitt trigger converts s the signal into square wave having fast
rise and full times.
* The square wave is then differentiated and clipped.
* Each pulses is proportional to each cycle of unknown signal.

8. Start - Stop Gate
* The output from schmitt trigger to applied to start and stop gate.
* When the gate is open, input pulses are allowed to pass through it.
* A counter will now start to count these pulses.
* When the gate is closed input pulses are not allowed to pass through the gate. The
counter will now stop counting.
Counter and Displayed
* The number of pulses during the period gate is open are counted by the counter.
* If this interval between start and stop condition is known, the frequency of unknown
signal is measured .

9. f = N/t
Where,
f = Unknown frequency
N = Number of counts displayed by the counter.
T = Time interval between start and stop condition of the gate.

10. * Frequency Counting
* Precise frequency measurements in radar based
application.
* Pressure, temperature, strain, and weight
measurements with proper transducer.
* Motor speed measurements are also possible with
proper arrangement.
* Microwave frequency measurements.