Filter circuit, continuous time filter, and signal reproducing apparatus

A filter comprising:

• a first voltage to current convertor configured to convert a first input voltage into a current using a transfer conductance as a conversion coefficient;
• a capacitor connected to an output terminal of the first voltage to current convertor;
• a second voltage to current convertor connected to the first voltage to current convertor and the capacitor, and configured to convert a second input voltage into a current using a transfer conductance as a conversion coefficient;
• a coefficient setting module configured to adjust the transfer conductance of the first voltage to current convertor from a first control signal and a second control signal indicative of gain adjustment and to generate a third signal to be used in gain adjustment, wherein
• the output terminal of the first voltage to current converting circuit is connected to an output terminal of the second voltage to current convertor, the output terminal of the second voltage to current convertor configured to output a signal inverted with respect to a signal from the first voltage to current convertor,
• the first voltage to current convertor is configured to receive the third signal and a fourth signal for frequency adjustment, and
• the second voltage to current convertor is configured to receive the first control signal and the fourth signal.

A continuous time filter for waveform equalization comprising:

• a first low pass filter;
• a second low pass filter;
• and
• a variable equalizer,
• wherein each of the first low pass filter, the second low pass filter, and the variable equalizer comprises a filter comprising:
• a first voltage to current convertor configured to convert a first input voltage into a current using a transfer conductance as a conversion coefficient;
• a capacitor connected to an output terminal of the first voltage to current convertor;
• a second voltage to current convertor connected to the first voltage to current convertor and the capacitor, and configured to convert a second input voltage into a current using a transfer conductance as a conversion coefficient;
• a coefficient setting module configured to adjust the transfer conductance of the first voltage to current convertor from a first control signal and a second control signal indicative of gain adjustment and to generate a third signal to be used in gain adjustment, wherein
• the output terminal of the first voltage to current convertor is connected to an output terminal of the second voltage to current convertor, the output terminal of the second voltage to current convertor is configured to output a signal inverted with respect to a signal from the first voltage to current convertor,
• the second voltage to current convertor is configured to receive the first control signal, and
• a frequency band is adjusted by the first control signal.