Quadrature Downconverter The SL1710 is a quadrature downconverter, intended for use with both Professional and Consumer Digital Satellite Applications. The device contains high linearity, low noise amplifiers, quadrature mixers, plus an on-chip oscillator, operating between 350MHz and 500MHz, which may be synthesised via the differential prescaler outputs. An AGC with 18dB gain control is provided to cope with a wide range of input signal levels. I and Q outputs are via low impedance single ended amplifiers. These may be connected to a dual channel analog to digital converter such as the PCA916, VP216, VP215 or VP213, via a suitable anti-alias filter. FEATURES ■ Wide input frequency range (350-500MHz) ■ On chip oscillator with varactor tuning or SAW resonator operation capability ■ Nominal 40dB conversion gain from IF input to I and Q outputs ■ AGC amplifier with 18dB gain control range ■ I to Q phase match 90°C to ± 2°, gain match better than 1dB ■ Low impedance I and Q single ended outputs, with 15MHz ± 1dB BW ■ Divide by 32 prescaler outputs ■ Suitable for QPSK and up to 64QAM systems APPLICATIONS ■ Consumer digital satellite decoders ■ Professional digital satellite decoders ■ Communication systems
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