interested in a review of the design. If you are interested,
could you please look this over? Thank you.
----------------------------------------------------
This is for a system that uses a PC, custom software
(written by me), a hardware interface (to be built by
a specialist, not me), and one or two hydrophones
(off-the-shelf). In the one-hydrophone option, the
hydrophone is to be used for input and output. In the
dual-hydrophone option, one h-phone is for input and
the other is for output.
Somewhat a priori numbers:
Usable frequency range (underwater acoustics): 1 to
100 kHz
For Input:
Voltage sampling = 200 kS/s (S/s = Samples per second)
Voltage array size = 1024 samples
Voltage sample size = 16 bits
For output, the application sends a voltage sample to
the hardware at the voltage rate, 200 kS/s, and the
hardware converts this voltage number into the analog
equivalent. If a single hydrophone is used, then the
input process may be disabled during the output.
The connection standard used in and out of the PC =
USB version 2 (max device speed = 1500 kBytes/s)
The PC application needs to get a voltage array at
each 100th of a second, i.e., the frequency sampling
rate is 0.01 second. Frequency Sampling Rate = 100 F/s
(F/s = Frequency samples per second). A frequency
sample is a single number which is the dominant
frequency resulting from an FFT calculation on a
voltage array. The frequency sample is done by the
software of the application (it is already written).
The two input frequency sampling options are these:
1) Continuous feeding of voltage numbers to PC memory:
The A/D hardware sends to the PC voltage samples
continuously at the rate of 200 kS/s. The voltage
samples are stored in a PC memory buffer which is read
by the application once every 100th of a second.
The data traffic between the PC and the A/D = 400 kB/s
= 200 * 2
= voltage sampling * voltage sample size
2) Selective voltage numbers to PC:
The A/D hardware sends to the PC a voltage array at
each 100th of a second (frequency sampling rate = 0.01
sec), either automatically or when requested by the PC
(at each 100th of a second).
The data traffic between the PC and the A/D = 200 kB/s
= 1024 * 2 * 100
= voltage array size * voltage sample size * frequency
sampling
The voltage samples are stored in a PC memory buffer
which is read by the application once every 100th of a
second.
I would be grateful for any comments. For example,
which option is the most appropriate or effective, or
which option is the least expensive (if both options
are equivalent in effectiveness).
I would also welcome suggestions on who could
manufacture the A/D hardware or who already sells such
hardware, off-the-shelf, and compliant with these
requirements, with a preference for Option 2)
Selective voltage numbers to PC, and a single
hydrophone instead of 2.
thanks
serge masse
[EMAIL PROTECTED]
<a href="http://leafy.dev.java.net/";
rel="nofollow">http://leafy.dev.java.net/</a>
|