low frequency meter problem?

Status
Not open for further replies.

fireplus

Full Member level 3
Joined
Oct 31, 2003
Messages
182
Helped
7
Reputation
14
Reaction score
3
Trophy points
1,298
Activity points
1,633
hi,

may some body help me in how can i measure low frequency signal such as 50.73hz the most important is 0.73hz with small gate time like 0.2 sec
i made a frequency meter that can measure 500khz to 1 hz with a gate time 1 sec
but what about lower than 1hz frequency ?

Thanks for every body want to help

Fire in The Wire :idea:
 

Hi fireplus!

Use the low frquency signal as the gating pulse along with a clock to measure pulse width. Calibration of this result gives frequency.

Giri
 

hi,
but i still have to waite for more than one second for 0.3hz wave
is there any different alogrithm to do that with small gate time

Fire in The Wire :idea:
 

Do a Google search for "frequency reciprocal counting" and I think you will find your answer.

For a graphical analysis of "zero crossing" versus "reciprocal counting" methods, by Michel Waleczek, you can look here:
https://www.m3electronix.com/recip.gif
 

    fireplus

    Points: 2
    Helpful Answer Positive Rating
I think using a triggered clock and a counter would do
the trick as Giri said. You need to trigger a clock when
the signal croos zero and count thepulses until the
next zero crossing . Ex., using half cycle of a 50 Hz
signal (20 MSec) to trigger a 10Mhz counting clock
will give you 100,000 counts, for a 50.3 Hz signal the
count would be 99,403.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…