Signal processing circuit and measurement system

A method for eliminating image portions, the method comprising the steps of:

• receiving an input signal with an initial bandwidth by a narrowband receiver;
• providing a local oscillator signal with a center frequency by at least one local oscillator of the narrowband receiver;
• mixing, by at least one mixer of the narrowband receiver, the input signal and the local oscillator signal to obtain a mixed signal including image portions, wherein the mixed signal has a respective center frequency in view of the local oscillator signal mixed therein;
• processing, by the narrowband receiver, two or more mixed signals, thereby obtaining two or more captured signals for different center frequencies of the local oscillator signal, wherein the mixed signals each are sectioned into signal sections with a bandwidth substantially equal to or less than a difference between the two or more different center frequencies, wherein the two or more captured signals have a limited bandwidth compared to the initial bandwidth;
• and
• combining the two or more captured signals in order to obtain a processed signal without image portions.

A measurement system for eliminating image portions, the measurement system comprising:

• a narrowband receiver configured to receive an input signal with an initial bandwidth, wherein the narrowband receiver comprises
• at least one local oscillator configured to provide a local oscillator signal having a center frequency, and
• at least one signal mixer configured to mix the input signal and the local oscillator signal to obtain a mixed signal including image portions, wherein the mixed signal has a respective center frequency in view of the local oscillator signal mixed therein,
• wherein the narrowband receiver is configured to process two or more mixed signals, thereby obtaining two or more captured signals for different center frequencies of the local oscillator signal, wherein the captured signals have a limited bandwidth compared to the initial bandwidth,
• wherein the narrowband receiver is configured to combine the two or more captured signals in order to obtain a processed signal without image portions, and
• wherein the narrowband receiver is configured to determine at least one scattering parameter associated with the processed signal.