Patent ID: 8285214

Claim:
Adjustable circuit for filtering of a transmission channel of an RFID signal and for suppression of a carrier signal in a reception path between an input gate and an output gate, with at least one adjustable oscillator for generation of an oscillator signal, with at least one input mixing stage cooperating with the oscillator for mixing of an input signal by the oscillator signal to an intermediate frequency, and with a blocking device which is arranged downstream of the at least one input mixing stage for suppression of the carrier signal at the intermediate frequency, wherein the blocking device has a first band-pass filter for filtering of a first sideband of the input signal and a second band-pass filter for filtering of a second sideband of the input signal, and wherein a power divider is provided for division of an input signal between a first path and a second path, that at least one first adjustable oscillator is provided for generation of a first oscillator signal, that in the first path a first input mixing stage cooperating with the first oscillator is provided for mixing of the input signal by the first oscillator signal to a first intermediate frequency, that the first band-pass filter is arranged downstream of the first input mixing stage for filtering of the first sideband of the input signal at the first intermediate frequency, that in the second path a second input mixing stage cooperating with the first oscillator or a second oscillator for mixing of the input signal by the oscillator signal to a second intermediate frequency, and that the second band-pass filter is arranged downstream of the second input mixing stage for filtering of the second sideband of the input signal at the second intermediate frequency.