US 5,634,207 A · Frequency converter capable of reducing noise components in local oscillation signals

Abstract

A frequency converter includes a high-frequency signal input circuit for forming a high-frequency signal with bias voltage or current to output a bias-added high-frequency signal; a local oscillation signal input circuit having a first element for forming a local oscillation signal with bias voltage or current and an element for suppressing a noise component having a frequency near a frequency of multiple of even number of a local oscillation frequency to output a bias-added and noise suppressed local oscillation signal; and a multiplication circuit for multiplying the bias-added high-frequency signal and the bias-added and noise suppressed local oscillation signal. By the constitution, it is possible to convert the high-frequency signal into a desired frequency signal having low influence of noises having frequency near the frequency of multiple of even number especially zero or two of the local oscillation signal to thereby reasonably suppress gain and noise in the high-frequency amplifier and local oscillator and reducing a current consumption of a radio receiver.

Claims12

Dependent claims

A frequency converter capable of reducing a noise component in a local oscillation signal:

comprising
a high frequency signal input circuit for inputting a high-frequency signal, for producing the high-frequency signal with bias voltage or current, and for outputting a bias-added high-frequency signal;
a local oscillation signal input circuit for inputting a local oscillation signal, and including at least bias adding means for outputting a bias-added local oscillation signal after adding the local oscillation signal with bias voltage or current, and even harmonic suppression means for suppressing a noise component having a frequency in the vicinity of a frequency which is multiple of even number of a local oscillation frequency of the local oscillation signal so as to output a bias-added and even-noise suppressed local oscillation signal in which noises having frequency of multiple of even number are reduced;
and
a multiplication circuit for inputting the bias-added high-frequency signal supplied from the high-frequency signal input circuit and the bias-added and even-noise suppressed local oscillation signal supplied from the local oscillation signal input circuit, and multiplying both the signals to output a product of the bias-added high-frequency signal and the bias-added and even-noise suppressed local oscillation signal.

2 more elements

A radio receiver system capable of reducing a noise component included in a reproduced signal, comprising

a reception section for receiving a radio frequency signal including a high-frequency signal through an antenna:
a frequency converter section including a high-frequency signal input circuit for producing a high-frequency signal inputted from the reception section with bias voltage or current, a local oscillation signal input circuit for adding, to bias voltage or current, a local oscillation signal having a local oscillation frequency substantially equal to a frequency of the high-frequency signal received by the reception section to output a bias-added local oscillation signal and for suppressing a noise component having a frequency near a frequency multiple of even number of the bias-added local oscillation signal to output a noise suppressed signal, and a multiplication circuit for multiplying the bias-added high-frequency signal and the noise suppressed local oscillation signal;
and
a signal processing section for inputting a converted signal supplied from the frequency converter section and outputting a desired frequency signal which is generated by eliminating a signal component of an unnecessary frequency band from a converted signal end including only a signal component proper for a reproduction.

1 more element

Dependencies are inferred from the claim text.

Frequency converter capable of reducing noise components in local oscillation signals

Life of this patent

Frequency converter capable of reducing noise components in local oscillation signals

Life of this patent

Abstract

Claims12