Yahoo Groups archive

Doepfer

Index last updated: 2026-04-29 00:15 UTC

Message

Re: Frequency reading on an oscilloscope?

2007-10-30 by Tim Stinchcombe

Hi Bryan,

> I'm rather new to oscilloscopes and I was wondering should I expect 
it to be able to tell me the frequency of a slow-moving CV.  I'm not 
seeing a way to read the frequency of a wave.

As long as your slow-moving CV is actually repetitive, then you 
should be able to do it by measuring the time it takes for the 
pattern to repeat. I don't know what facilities that scope has, but 
often scopes have cursors you can move around the screen, and it will 
tell you the readings of where they are, and then take the 
difference. If not, then you will have to judge it for yourself, from 
the timebase setting of 'so many seconds per division'. Do this at 
two points where the pattern repeats, for example the peaks, or where 
the wavefrom crosses the zero line *in the same direction*: this is 
called the 'period' of the signal. Then simply divide this into 1 to 
get the frequency, so frequency = 1/period.

Try it on something you know first, to check that you have the hang 
of it, for example, for middle C coming out of one of your 
oscillators you should see the time difference as about 0.0038 
seconds = 3.8 milliseconds, so 1/0.0038 = 263Hz (middle C actually 
261.63Hz). For a slow moving waveform it is likely that you will have 
to 'freeze' the display after one pass to be able to make a 
measurement if the timebase is set very slow.

Tim

Attachments

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.