zazula@uazhe0.physics.arizona.edu (RALPH ZAZULA) (02/06/91)
I expect to get my '030 cube from Bland within the next 2 weeks
and the first project I am gearing up for (besides installing
my HD) is building a 16-bit, dual-channel, 50KHz bandwidth,
A/D converter for use with the DSP chip (primarily - audio
recording). What I need to know is : is the
basic documentation that comes with the NeXT enough to tell me
how to interface with the DSP "C" port? I need to know what
signals are required to send data to the DSP. I thought I saw
somewhere that the DSP port has a similar protocoll as RS-232
or something? Is that right?
I saw postings saying that the NeXT Technical Docs. weren't being
shipped yet. Is there any other source for info on the 56001?
Thanks,
Ralph Zazula
P.S. if anyone is intersted, I'm using a 100KHz f_s(max) dual 18-bit
A/D chip with SNR 90dB, on-chip S/H, automatic linearity error
correction, guaranteed linearity accuracy of 15 bits......
(quite a slick chip, if you ask me!)
|----------------------------------------------------------------------|
| Ralph Zazula "Computer Addict!" |
| University of Arizona --- Department of Physics |
| UAZHEP::ZAZULA (DecNet/HEPNet) |
| zazula@uazhe0.physics.arizona.edu (Internet) |
|----------------------------------------------------------------------|
| "You can twist perceptions, reality won't budge." - Neil Peart |
|----------------------------------------------------------------------|cyliao@eng.umd.edu (Chun-Yao Liao) (02/21/91)
For your information about A/D converters, here goes a list of "good" ones
To save time, I will only list those 16 bits and up ADC
Micro Networks (508) 852-5400
True 16-bit A/D combines allfunctions in single package.
MN6400, self-calibrate, sampling up to 50 KHz true 16 bits
sampling even in extended temperature range applications.
It combines an inherent track and hold function,
analog input buffer, reference, clock and
control logic circuitry, ad a paralel data-bus driver in a single
package.
88db SNR, -98db harmonic sampling at 1kHZ full scale analog input.
$175/100
Atmel Corp. (408) 441 0311
Dual 18 bit ADC uses single +5v supply
AT76C120. conversion speed less tahn 10 us, input bandwidth of
50kHZ, guaranteed linearity accuracy level of 15 bits.
it resolve input signals of less than 10 uV. 86 to 90 db SNR. on chip
sample-and hold amp, auto linearity error correction. output code
is serially in 2's complement
$25/1000 available now
UltraAnalog, Inc 415 657 2227
20 bit audio A/D (eleminates anti-aliasing filter)
ADC 20048 20-bit. 128 times oversampling, noise-shaping algorithm
that eliminates the need for anti-aliasing filters. 40 times
improvement in differenntial linearity compared to conventional. 108
db dynamic range, frequency response flat to withing +-.05db.
THD +N of -96db. Operate from +-15v and +-5v
$199/100
Datel, Inc 508 339 3000
ADS930 16 bit, 500kHz. differential input and on board 16-word
FIFO memory. two control pings allow users to read the memory when half
full, full, or on command. -95db THD, 95db SNR
+5v and +-15v, 2.1W
$374
Analogic Corp 508 977 3000
ADC4355/56/57 low-noise, low-distortion 16 bit. 100 and 200 kHz
96db dynamic range, 95db SNR, -103db THD at 1kHz. +-15v and +5v
$237.15/$226.75/$264.15 in quant of 100
hope these helps.
--
cyliao@bagend.eng.umd.edu o Q. Who am I?
@wam.umd.edu o A. A NeXTed person with "small" HD and OD
@epsl.umd.edu o An Apple // guy
xxxxxx@xxxxxx.xxxx.xxxxxxx.xxx o An airplane pilot (I hope)