From: b-clark@nwu.edu (Brian Clark)
Subject: Re: High Resolution ADC for Mac II
Nntp-Posting-Host: elvex34.acns.nwu.edu
Organization: Northwestern University
Lines: 28

In article <b-clark-160493183822@elvex33.acns.nwu.edu>, b-clark@nwu.edu
(Brian Clark) wrote:
> 
> I don't know about the Instrutech boards (though I plan to check them out),
> but you need to be very careful checking the monotonicity and S/N ratio of
> many of the "16 bit" boards out there. The NI boards are very clearly
> specified in terms of monotonicity, S/N ratio, accuracy, etc; and the
> NB-A2100 and NB-A2150 have all the dyynamic range and freedom from
> distortion that you'd expect from a good, true 16 bit converter. This is
> not true for the Spectral Innovations boards, for example.

To boorishly reply to myself, I found I did have the Instrutech information
already. The specs (to use the term loosely) are as follows:

A/D: 16 bit converter, with 14 bit accuracy to 100 kHz, 12 bit accuracy to
200 kHz. No specs for S/N, monotonicity, linearity. There are 8 multiplexed
inputs sharing the single A/D, so that all inputs are not samples at the
same time, and in the above conversion specs the all-channel sample rate
must be used. Thus, for two channels, you only have 14 unknown quality bits
at 50 kHz per channel. This is poorer quality than the national
Instruments, at the same sample rate.

D/A: 16 bit converter. No specs for S/N, monotonicity, linearity. Each of
the 4 output channels has its own converter.

The price for the external converter box (the ITC-16), the NuBus interface
board (the MAC-23), plus C driver software and Igor XOP's is $2695. Rather
steep.
