A Double-Conversion Broad Band TV-Tuner with GaAs Ics

In conventional terrestrial TV tuners single down conversion is applied comprising three tuners in parallel for reception of the TV frequency band (47-860 MHz). As a consequence 12 tunable resonant circuits have to be adjusted manually for good frequency tracking. A monolithic solution, instead, avoids tweaking of the different tuning circuits and reduces the number of components. Both measures are steps to a costeffective approach. In this paper, a double-conversion broad band tuner based on GaAs-ICs is presented. Its gain (20 dB), noise figure (7.5 dB) and in-channel cross modulation (6 mV) correspond to the state-of-the-art of conventional tuners. Based on an analysis of the measured results necessary improvements in off-channel cross-modulation are discussed.