| 摘要 |
An HF receiver head having high sensitivity and capable of receiving variable-level input signals has characteristics which are adjusted as a function of the received signal level. The HF head essentially comprises a generator for delivering control voltages as a function of the amplitude of the received signals. The dynamic range of the input amplifier and of the mixer can thus be varied as a function of the received signal level up to a predetermined threshold value. Above this threshold value, an input attenuator assumes increasing values which makes it possible to attain a wide dynamic range of the HF head under optimum conditions of sensitivity and linearity.
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