PLL as a tone filter.
 

I need to filter noisy signal with a single frequency tone falling in
the pass band 67 to 250 Hz and am looking at using a 567 PLL or an
XR-215A or the like. It appears that the bandwidth of these are quite
narrow as they are usually used as tone decoders. Any suggestions? I
want to obtain as clean a tone out as possible.

The application is to regenerate a CTCSS tone. Simplicity counts!

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

PLL as a tone filter.
 

On Sat, 17 Mar 2007 01:25:47 -0400, **THE-RFI-EMI-GUY**
wrote:

I need to filter noisy signal with a single frequency tone falling in
the pass band 67 to 250 Hz and am looking at using a 567 PLL or an
XR-215A or the like. It appears that the bandwidth of these are quite
narrow as they are usually used as tone decoders. Any suggestions? I
want to obtain as clean a tone out as possible.

The application is to regenerate a CTCSS tone. Simplicity counts!
I used a 567 PLL many years back as a Morse Code audio filter for CW.
It worked pretty well.

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"

PLL as a tone filter.
 

bandwidth is narrow, but width mite be adjusted, but you will lose the sharp
edge of the cutoff

perhaps use one of those excellent new active filter chips. add a few
capaciors and you have some really tight band filters with db drops near
60db!

http://www.circuitsage.com/filter.html



"**THE-RFI-EMI-GUY**" wrote in message
...
I need to filter noisy signal with a single frequency tone falling in
the pass band 67 to 250 Hz and am looking at using a 567 PLL or an
XR-215A or the like. It appears that the bandwidth of these are quite
narrow as they are usually used as tone decoders. Any suggestions? I
want to obtain as clean a tone out as possible.

The application is to regenerate a CTCSS tone. Simplicity counts!

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P