Matrox Solios eA, Установка и справочник по оборудованию, Страница: 76 / 196

76 Chapter 4: Matrox Solios hardware reference
There are three ways to program the reference levels and the attenuator. You can
specify the actual black and white voltage levels of your input signal and have the
software calculate appropriate values for each element in the offset-gain topology.
You can have the software emulate an A/D with programmable black and white
references and specify the levels as a percentage of their possible values.
Alternatively, you can specify the required values for the offset and the gain
controls. If the signal amplitude is specified as greater than 1.1 V, the attenuator
will be enabled automatically. In all cases, you use the MIL-Lite function
MdigReference() or MdigControl() .
Low-pass filter
The low-pass filtering stage is used to limit high frequency noise and aliasing effects
at the input of the A/D converter. Each acquisition path has two filters. The filters
used on Matrox Solios are 4th order Butterworth filters. The first has a -3 dB
cutoff frequency of 33 MHz. The second filter has a -3 dB cutoff frequency of
7.5 MHz, useful for RS-170 and CCIR video sources. All filters provide
80 dB/decade or 24 dB/octave of attenuation for frequencies above the cutoff
value. Enable the low-pass filters using the MIL-Lite function
MdigControl() with
M_INPUT_FILTER
.
10-bit A/D converters
Matrox Solios eA/XA uses high-quality, high-speed, 10-bit analog-to-digital
(A/Ds) converters to sample the video signal. Therefore, Matrox Solios eA/XA
provides excellent digitization quality, even at the highest sampling frequency. The
A/D converters can accept inputs from 5 MHz to 65 MHz, allowing full use of
their sampling speed.
Lookup tables
Matrox Solios eA/XA has programmable lookup tables (LUTs). For Matrox Solios
eA/XA Quad, the LUTs can be operated as one, two, three, or four 1024-entry
8- or 16-bit LUTs. For Matrox Solios eA/XA Dual, the LUTs can be operated as
one or two 1024-entry 8- or 16-bit LUTs. For Matrox Solios eA/XA Single, the
LUTs can be operated as a 1024-entry 8- or 16-bit LUT
1
.
The LUTs are programmed using the MIL-Lite function MdigLut() .
1. For example, two 1024-entry 8-bit LUTs can map 2-tap 10-bit data to 8-bit values.