[sci.electronics] recording via induction: is it possible?

daniel@hexagon.se (Daniel Deimert) (03/11/91)

I was wondering if it would be possible to record an analogue signal
(i.e.  the one in a loud-speaker's cable) on a tape recorder.  Or rather
if the resulting signal is of good or poor quality.  S/N ratio?

Would the circuitry needed be complicated?

Please e-mail suggestions to me!

Regards,
Daniel

-- 
Daniel Deimert, daniel@hexagon.se or ...!sunic!kullmar!pkmab!hexagon!daniel

larry@kitty.UUCP (Larry Lippman) (03/13/91)

In article <3012@hexagon.se> daniel@hexagon.se (Daniel Deimert) writes:
>I was wondering if it would be possible to record an analogue signal
>(i.e.  the one in a loud-speaker's cable) on a tape recorder.  Or rather
>if the resulting signal is of good or poor quality.  S/N ratio?

	One can obtain a reasonably good signal through use of an inductive
clamp-on current probe intended for oscillographic measurement purposes.
Both Tektronix and Hewlett-Packard manufacture such probes, which permit
a conductor diameter up to about 3/16 inch.  It is necessary to amplify
the output of the current probe.  It is also important to remember that
the current probe goes over only *one* conductor of a cable.

>Would the circuitry needed be complicated?

	Not at all.  However, one must have a suitably designed probe;
an Amprobe AC ammeter probe intended for power measurements would function
rather poorly on audio signals.

Larry Lippman @ Recognition Research Corp.  "Have you hugged your cat today?"
VOICE: 716/688-1231       {boulder, rutgers, watmath}!ub!kitty!larry
FAX:   716/741-9635   [note: ub=acsu.buffalo.edu] uunet!/      \aerion!larry