Passive frequency mixer

Abstract

The present invention discloses a passive mixer which comprises an input resistance circuit that including: a first electric resistance, a second electric resistance and a switch tube that connected in series, wherein, source electrode and drain electrode of the switch tube is respectively bridge connected to two ends of the first electric resistance, and grid of the switch tube is connected to local oscillation signal VLOO while the drain electrode is connected to voltage signal VIN; a switch converting circuit that used to frequency convert electrical current signal flow from converted VIN under control of VLOO by input resistance to output frequency; electrical current voltage convert circuit that used to convert electrical current signal after frequency conversion to voltage signal to output. Through adopting switch tube in input resistance branch path, harmonic interference can be effectively dispelled, and problems like harmonic interference oversize and that leading to output desired signal most likely be inundated by harmonic interference signal hence system unable work in existing passive mixer can be overcome.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a passive mixer. Background technique [0002] Mixers are important blocks in semiconductor integrated circuits. Generally, the mixer is driven by a local oscillator (Local Oscillation) signal of a specific frequency, and the input signal is multiplied by the local oscillator signal to generate the first harmonic frequency of the input signal frequency and the local oscillator signal and the higher harmonic of the local oscillator signal. The sum of the frequencies, and the output signal of the frequency component of the input signal frequency and the difference between the first harmonic frequency of the local oscillator signal and the higher harmonic frequency of the local oscillator signal. Usually only the frequency component of the combination of the input signal and the first harmonic of the local oscillator (we call it the fundamental wave) is the useful signal we want,...

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to provide a passive mixer, which can solve the problem that the passive mixer in the prior art has too much harmonic interference, and the output useful signal is likely to be submerged by the harmonic interference signal, causing the system to fail question

[0011] The above embodiments can effectively eliminate harmonic interference by using a switch tube in the input resistance branch, and overcome the excessive harmonic interference of passive mixers in the prior art, which may cause the useful output signal to be interfered by harmonics The signal is overwhelmed, causing the system to fail to work

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