Sampling filter device

A sampling filter device comprising:

• a first voltage current converter which converts an input voltage signal into a current;
• a first integration unit which samples the current output from the first voltage current converter and integrates the sampled current;
• a local oscillator which outputs a reference clock;
• and
• an integration time duration control unit which generates an integration time duration control signal for controlling integration time duration in the first integration unit based on the reference clock, and makes the integration time duration variable, thereby performing weighting of a filter characteristic of the sampling filter device in response to the variable integration time duration, wherein the integration time duration control unit has a control signal generator to which the reference clock, an inverse phase signal to the reference clock, an addition signal provided by adding a signal whose phase is 90° different from that of the reference clock to the reference clock, and a signal provided by adding the addition signal to the inverse phase signal to the reference clock are input, and which is controlled by a signal of a double frequency of the reference clock.

A sampling filter device comprising:

• a first voltage current converter which converts an input voltage signal into a current;
• a first integration unit which samples the current output from the first voltage current converter and integrates the sampled current;
• a local oscillator which outputs a reference clock;
• and
• an integration time duration control unit which generates an integration time duration control signal for controlling integration time duration in the first integration unit based on the reference clock, and makes the integration time duration variable, thereby performing weighting of a filter characteristic of the sampling filter device in response to the variable integration time duration, wherein the integration time duration control unit has:
• a first dividing-type phase shifter which generates a first signal provided by dividing a clock having a double frequency of the reference clock and a second signal whose phase is 90° different from that of the first signal;
• a second dividing-type phase shifter which generates a third signal provided by dividing an inverse phase signal to the clock having the double frequency of the reference clock
• a first adder which outputs a fifth signal provided by adding the first signal to the second signal;
• a second adder which outputs a sixth signal provided by adding the third signal to the second signal;
• and
• a control signal generator for generating the integration time duration control signal based on the first signal, the third signal, the fifth signal, the sixth signal, and the clock having the double frequency of the reference clock.

A sampling filter device comprising:

• a first voltage current converter which converts an input voltage signal into a current;
• a first integration unit which samples the current output from the first voltage current converter and integrates the sampled current;
• a local oscillator which outputs a reference clock;
• and
• an integration time duration control unit which generates an integration time duration control signal for changing integration time duration in the first integration unit based on the reference clock, wherein
• the first integration unit integrates the sampled current during the integration time duration, thereby performing weighting of a filter characteristic of the sampling filter device in response to the variable integration time duration changed, the sampling filter device further comprising a second voltage current converter arranged in parallel with the first voltage current converter and having a gain different from that of the first voltage current converter, wherein
• the first integration unit samples the current output from the first voltage current converter or the second voltage current converter, and integrates the sampled current, and
• integration charge amount per unit time in the first integration unit is varied by switch control of the first voltage current converter and the second voltage current converter.