jbn@glacier.STANFORD.EDU (John B. Nagle) (11/17/87)
I'd like to use the audio outputs of an Amiga 1000 for a non-audio
application, control of mirror galvanometers. Are the outputs DC-coupled,
allowing one to generate signals all the way down to DC, or is there
capacitive coupling in the circuit? Has anyone tried using these
analog outputs for control purposes?
Also, if the electrical specs for the outputs are known, I'd like
to see them.
John Naglegrr@cbmvax.UUCP (George Robbins) (11/18/87)
In article <17221@glacier.STANFORD.EDU> jbn@glacier.STANFORD.EDU (John B. Nagle) writes: > > I'd like to use the audio outputs of an Amiga 1000 for a non-audio > application, control of mirror galvanometers. Are the outputs DC-coupled, > allowing one to generate signals all the way down to DC, or is there > capacitive coupling in the circuit? Has anyone tried using these > analog outputs for control purposes? They are AC coupled and low-passed filtered. > Also, if the electrical specs for the outputs are known, I'd like > to see them. They really aren't specified, except as being audio-frequency outputs, nominal 1 V signal into 2 K Ohm line, anti-aliasing filter starting at 4 KHz, effective cutoff at 7 KHz, noise spectrum peaks at 60 Hz, 15.75 KHz and harmonics. There are DC coupled analog outputs readily accessible at test points TP2 and TP3, however you need to evaluate the analog noise level and accuracy relative to the needs of your proposed application. You might want to consider operating one or more of of those "microprocessor compatible" DAC modules or chips off of the parallel port. This would allow a much better degree of ground isolation and noise decoupling, not to mention better DAC specifications. -- George Robbins - now working for, uucp: {uunet|ihnp4|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@uunet.uu.net Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)