1985-86: The Satvrn QD, promoting the concept of "Quasi-DBS" with
high channel counts on low-to-medium power satellites in the FSS band -- a concept
which we had championed in Europe since 1982 and which was eventually to be realized
in 1989 with the Astra system. The QD covered 950 to 1700 MHz with an
injection-locked threshold-extension demodulator and prescalers for frequency-synthesized
But please note the tuners shown on this page are only an illustration of our capabilities.
They do not necessarily represent designs available for licensing to manufacturers --
indeed most are already bound by existing licences.
1987-88: The RWTDM-0800, used in the original Paytel IRD and later in the Wolsey (AB Group, Wales) "Starlet" Astra receiver and BSB D-MAC SMATV receiver. It was our first design to feature single-point alignment and two compartments, at a time when most tuner manufacturers had eight or more alignment points in an average of six compartments, and some were even using separate enclosures (cans) for tuner and demodulator.
1988-89: The RWTDM-1100, a version of the 0800 but with threshold extension and on-board prescaler, commissioned by Amstrad in association with Sky for the SRX100/200/200E Astra receiver and later used in the ground-breaking SRD400 IRD. In 1991 Amstrad had over 70% of the European market share in satellite receivers, and RWT's 1100 had outsold all other satellite tuners, world-wide:
1990-91: A further development of the 0800, the RWTDM-1100 Iss.15 provided dual inputs, dual bandwidths, PLL frequency synthesis over 950 to 1750 MHz, PAL/MAC switched threshold optimisation and FTZ EMC compliance for European markets. The 1100/15 was used in the Amstrad SRD600 Multi-MAC and PAL VideoCrypt IRD, which pioneered the RWT innovation of 22kHz LNB band-switching:
1991-92: A totally new design for Amstrad, the RWTDM-1300 introduced a series of cost-saving measures, while extending dynamic range to cope with the ever- increasing number of carriers from the Astra orbital slot at 19.2 degrees East. As well as the SRX310/SRD510 series it was used in the dual-tuner model SRX330, to permit simultaneous VCR recording of one satellite channel while viewing another:
1992: Developed from the 1300, the RWTUN-1400 provided access to Germany's DSR -- Digital Satellite Radio -- a QPSK multiplex at 20.48Mb/s carrying 16 channels of uncompressed CD-quality stereo sound. The Amstrad DSR100 receiver also housed a cable tuner.
1993: Another totally new design, the 1500 series succeeded in adding dual inputs with LNB RF and DC switching, 22kHz tone generation, dual IF bandwidths, PAL/MAC threshold switching, single supply operation and extended tuning range of 700 to 2050 MHz, without any increase in cost and with no compromise on performance. The 1500 was employed in the Amstrad SRX350/SRD550 range. The variant illustrated here is the RWTDM-1520 with auxiliary IF output, as used in the SRX/SRD 1000/2000 range of receivers and IRDs:
1994-95: The RWTRX-1600 series was designed as a complete analogue satellite receiver on a card, for integration into TVs, VCRs, PCs as well as for the stand-alone set-top box. The frequency-synthesized tuner covers 700 to 2150 MHz with 22kHz tone generation, a PAL-enhanced threshold extension demodulator, followed by a video processing section which includes de-emphasis, low-pass filtering, clamping and decoder switching, and an audio chain featuring 5.5 to 8.5 MHz subcarrier range, stereo phase-lock demodulators, compatible noise-reduction processors and output switching. Shown here is the RWTRX-1635, as used in the SRD700:
1995: The digital equivalent of the 1600 concept, the RWTDC-1700 series provides a module integrating satellite tuner with quadrature demodulator, dual ADC, QPSK clock and carrier recovery and concatenated Viterbi/Reed-Solomon FEC, all on a single card. It is functionally equivalent to the tuner/channel decoder modules employed in the IRDs for such systems as DirecTv, MultiChoice, Thaicom and Star TV, and is fully DVB compliant. Versions are now in development using single-chip channel decoder silicon from three major IC manufacturers:
Outline specification of compact tuners.
But please note the tuners shown on this page are only an illustration of our capabilities. They do not necessarily represent designs available for licensing to manufacturers -- indeed most are already bound by existing licences.
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