Adjustable circuit and RFID reader device

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.