Anritsu Electric Co., Ltd.

Toshihiro Kashiwagi

A multi-superheterodyne receiver having a first local oscillator for generating a first local frequency signal, a first frequency converter for converting to a first intermediate frequency signal a received signal in response to the first local frequency signal, a second local oscillator for generating a second local frequency signal, a second frequency converter for converting to a second intermediate frequency signal the first intermediate frequency signal in response to the second local frequency signal, includes judging circuitry for judging if a residual spurious component is generated when harmonic waves of at least one of the local frequency signals are at certain frequencies. Control circuitry shifts the first local frequency signal by a first predetermined frequency to cause the first intermediate frequency signal to suppress the residual spurious component, and shifts the second local frequency signal by a second predetermined frequency to maintain the frequency of the second intermediate frequency signal constant, when the judging circuitry determines that a residual spurious component will be generated at a preset receiving frequency. Thus, intermodulation disturbances in the receiver are suppressed.

Multi-superheterodyne receiver

A measured signal is supplied to an indication section through a high-frequency amplifier, a frequency converter, and an intermediate frequency amplifier. A predetermined local oscillation signal from a local oscillator is supplied to the frequency converter. A reference signal generator generates harmonic pulses having a uniform level at a spectral interval substantially equal to or larger than the predetermined passband of the intermediate frequency amplifier, the uniform level being used to calibrate a level of the signal to be measured. A frequency setting section sets the frequency of the measured signal. A first switching section switches an input to the high-frequency amplifier to an output side of the reference signal generator in accordance with the frequency set by the frequency setting section. A control section controls an oscillation frequency of the local oscillator so as to set an indicated value at the indication section to a maximum value while an output from the reference signal generator is supplied to a high-frequency amplifier, and controls a gain of an amplifier such that the indicated value at the indication section is set to a predetermined indicated value while the local oscillator is being operated to provide the maximum value. And a second switching section switches the input to the high-frequency amplifier to an input side of the measured signal after gain control is performed by the control section.

Growing community of inventors

Ebina, Japan

Toshihiro Kashiwagi