Anritsu Corporation

Yuji Kishi

Toru Otani

Momoko Inadomaru

Kenichi Watanabe

The present invention provides a filter bank circuit capable of measuring or testing a frequency band, a spectrum analyzer, a signal analyzer, a signal generator using the filter bank circuit, and a method for controlling the filter bank circuit. A filter bank circuitincludes, for example, a one-pole two-throw changeover switchand filter groups Gand G, each of which has m filters. The passbands of the filters included in each filter group do not overlap with each other, and the adjacent passbands of the filters included in all the filter groups overlap with each other.

Filter bank circuit, spectrum analyzer, signal analyzer, signal generator using the same, and control method for the filter bank circuit

There is provided a spectrum analyzer and a spectrum analysis method capable of promptly performing measurement while preventing the spectrum waveform caused by the fractional spurious components from being displayed. When the width of a designated span (analysis target frequency range) is larger than a boundary value, a reference signal frequency is set to a predetermined reference value, and a loop filter band narrower than a RBW (resolution bandwidth) is selected to thereby make the fractional spurious components be within the RBW and prevent it from being displayed as a spectrum waveform. Further, when the width of the designated span is smaller than a boundary value, the reference signal frequency is shifted from the reference value by a predetermined value so as to increase the frequency differences between the fractional spurious components and the main signal component of a VCO output signal by an amount equal to the product between the shift amount and the integer part of the frequency division ratio, and the band of the loop filter is set in accordance with the region including the RBW in a range narrower than the increased frequency difference so as to suppress the levels of the fractional spurious components.

Spectrum analyzer and spectrum analysis method

A frequency conversion unit converts the frequencies of input signals into intermediate frequencies using a predetermined local oscillation frequency. A sweeping unit sweeps the local oscillation frequencies in a predetermined sweeping time. A filter selectively passes signals having frequency components of a predetermined bandwidth based on signals sent from the frequency conversion unit. An A/D converter samples signals that have passed the filter and converts them into predetermined digital data. A signal processing unit processes signals, extending the digital data saved in the data storage unit into frequency spectrum data. A correction data storage unit saves the correction data of the delay times for the bandwidth in the filter. Based on the correction data saved in the correction data storage unit, a control unit changes the timing at which data is sent from the A/D converter to the signal processing unit via the data storage unit, so that a measured frequency corresponding to the local oscillation frequency upon the start of sweep in the sweeping unit may be correlated with the data that corresponds to the measured frequency and has been saved in the storage unit, in a one-to-one relationship. An output unit provides frequency spectrum data that has been processed in the signal processing unit.

Growing community of inventors

Atsugi, Japan

Yuji Kishi