|
The DSP's serial port signals (DI, DO, ICK, OCK, ILD,
OLD, IBF, OBE, OSE and SY) are buffered with transceivers
and made available at the DB15 connector on the board's
endplate. The direction of all but DI and DO are jumper
selectable.
| Analog Input The
inputs of both channels are independently
amplified from unity to over 1000 times by trim
pots accessible from the top of the card. Using
sigma-delta modulation, 64 times over-sampling
and a 3-stage digital FIR filter, the DBY3
achieves an 80 dB signal-to-noise ratio. The
anti-aliasing filters automatically track the
sampling rate so that no components have to be
changed with the oscillator. There is no external
triggering capability due to the nature of
sigma-delta converters. A high impedance (1M ohm)
is AC coupled but can be converted to DC coupled
with a jumper wire across each input capacitor.
If the input device requires a +5v bias, such as
a telephone handset, a space is provided for a
resistor on each channel to supply +5v from a
regulated source. This will reduce the input
impedance of the board.
Analog Output
The dual channel D/A converters have 8X
digital interpolation filters which track the
sampling rate set by the on-board oscillator.
They are followed by 64X oversampling sigma-delta
modulators and ultra-linear low-pass filters
which can drive +/-2v into a 600 ohm load.
|
Power
Requirements
|
| 320mA @ 5v 1.1mA @
+12v 1.1mA @ -12v |
Input
Specifications
|
|
Dual channel simultaneous sampling.
8 kHz to 50 kHz sampling rate.
64X oversampled sigma-delta A/D
converter.
Linear phase digital anti-aliasing
filters.
16-bit resolution.
|
| Dynamic Performance: |
| Dynamic range |
92.7
dB min. |
| S/(N+D) |
80 dB min. |
| THD |
.001% |
| Interchannel Phase Deviation |
.0001
degrees |
| Interchannel Isolation (dc to 20
kHz) |
100dB |
| DC Accuracy |
| Interchannel Gain Mismatch |
.05 dB max. |
| Gain error |
+/- 5% max. |
| Gain drift |
150 ppm/¡C max. |
| Analog Input |
| Input voltage range |
+/- 3.5 v |
| Input impedance (without 8.2k ohm
bias resistor) |
1M ohm |
| Group Delay |
16 sec / freq |
| (ex: At 50 kHz, there is a 320
usec delay from input of signal to output.) |
Output
Specifications
|
- Dual channel with zero phase error.
- 8 kHz to 50 kHz sampling rate.
- 64X oversampled sigma-delta modulator.
- 8X interpolation filters.
- 600 ohm drive capability.
- 16-bit resolution.
|
| Dynamic Performance (at 48
kHz) |
| Dynamic range |
93 dB min. |
| Idle channel S/(N+D) |
126 dB |
| THD+N (0 dB output) |
94 dB |
| THD+N (-20 dB output) |
75 dB |
| THD+N (-60 dB) |
35 dB |
| Passband to 3dB corner |
0 to 23.5 kHz |
| Passband to 0.0001 corner |
0 to 21.6 kHz |
| Passband ripple |
0.001 dB |
| Stopband |
26.4 dB |
| Stopband Attenuation |
90 dB |
| Interchannel Isolation (dc to 20
kHz) |
-80 dB |
| DC Accuracy |
| Interchannel Gain Mismatch |
.1 dB max. |
| Gain error |
+/- 5% max. |
| Gain drift |
150 ppm/¡C max. |
| Offset error |
+/- 1 mV |
| Output Voltage Range |
+/- 2.0V |
|
