frequency clamp
frequency clamp
(OP)
I am looking for a circuit to help me clamp off a 5 volt square wave at 1800hz. I have tried a few different things but I cant get it to work properly. Any help would be greatly appreciated.Yes I am a little new to this..





RE: frequency clamp
RE: frequency clamp
RE: frequency clamp
This, of course, means that you're passing lots of other sine waves up to 9000 Hz.
Otherwise, you're looking for a low-pass filter, but bear in mind that the cut-off frequency for a single pole filter is simply the frequency at which the response drops to 50% of that of the passband. A more complicated filter will introduce phase delays, which means that your square wave will get distorted in any case.
You need to review what you're trying to do. Perhaps a phase-locked loop might make more sense?
TTFN
RE: frequency clamp
RE: frequency clamp
Is the varying frequency due to the actual measurement, e.g., is it a frequency modulation proportional to the measured quantity? Does it need to stay a square wave? If you have some sort of demodulator than converts the frequency to a voltage, it may be easier to "clamp" the frequency after the conversion, since that could be as simple as a zener diode clamp.
TTFN
RE: frequency clamp
RE: frequency clamp
RE: frequency clamp
RE: frequency clamp
Here's an idea. Use a low pass filter (see Maxim for a good assortment of filter types and pole numbers) to make your 1800 Hz cutoff frequency. Then use further amplification and a comparator to re-create your square wave pulses after the filter.
Good luck,
Stan
RE: frequency clamp
you can make discrete TTL or CMOS logic or you can use
a microcomputer e.g. a PIC or a DOS STAMP.
If U need many pieces, use a cheaper micro. You can be
under $10 excluding PCB .
<nbucska@pcperipherals.com>