The Winersat WTM-860SL is a professional quality, digital headend component providing QPSK to QAM transmodula tion and RF upconversion functions in a single module.
The WTM-860SL accepts L-band RF inputs between 950 and 2150 MHz from the LNB at the satellite dish. The transmodulator then tunes selected satellite transponder and demodulates the QPSK signal. The forward error correction (FEC) embedded in the data stream is used to help retrieve an error free MPEG2 digital transport stream (TS) containing the desired digital programming multiplex.
The transmodulator then applies cable environment FEC to the transport stream and remodulates using QAM modulation to an IF QAM signal.
In RF upconverter, the IF QAM signal is SAW filtered and then upconverted to the desired output channel. Any standard CATV output channel may be selected in the range of 54 to 860 MHz. Bandpass flatness and phase noise are closely controlled in the WTM860 to ensure a high MER output signal. This ensures that the transmodulator will not introduce a source of errors into the distribution process. Because the MPEG2 transport stream information is not modified by the transmodulator, all encryption, authorization, and program guide information are passed on to the CATV set top box, without any changes. |
