3.1.3 G3 TRANSMISSION
The CIS picks up one line of image 1728 pels. The signal is then sent to the SDIP for digital processing. This processed data is paralleled out on the data bus and dumped into the T.4 to file buffer (MMR). After the data stored to T.4 to file buffer encodes, it is transfer to file to T.4 buffer (MR, MH, MMR) for transmission. The NS32FX200 generates a vector interrupt to the CPU to tell it to be ready for transmitting the image data. The NS32FX200 outputs the serial bit stream at sigma delta oversampling rate to the analog transmitter of the AFE. The serial bit stream is fed to a 7 bit D/A converter. This D/A converter is implemented by an analog switch, which selects either + 5V or -5V inputs. These voltages are filtered by an RC low pass filter to filter supply noise. The D/A output is filtered by three pole LPF with unit gain to attenuate the out-of-band quantization noise. The output of the LPF passes to the transformer through a 3 dB gain amplifier.
