Attenuation control device, signal attenuation device, automatic gain control device, attenuation control method, and automatic gain control method

An attenuation control method which is performed by an attenuation control device provided in a receiver of a high frequency signal to attenuate the high frequency signal, comprising:

• a data output step of outputting by a data output part digital data for controlling an amount of attenuation of the high frequency signal;
• a DA conversion step of performing by a DA converter DA conversion of the digital data into a control current for controlling a current which is passed through a PIN diode for attenuating the high frequency signal;
• and
• a current output step of outputting by the DA converter a corrected analog current as the control current so that a logarithmic value of the amount of attenuation of the high frequency signal is allowed to change linearly to the digital data.

An automatic gain control method which is performed by an automatic gain control device provided in a receiver of a high frequency signal to control a gain of the high frequency signal, comprising:

• an amplification step of amplifying, by an amplifier, the high frequency signal attenuated by a PIN diode for attenuating the high frequency signal;
• a strength detection step of detecting, by a signal strength detection circuit, a strength of the high frequency signal amplified in the amplification step;
• a data output step of outputting, by a data output part, digital data for controlling an amount of attenuation of the high frequency signal by the PIN diode, in response to a difference between the strength detected in the strength detection step and a predetermined reference value;
• a DA conversion step of performing, by a DA converter, DA conversion of the digital data into a control current for controlling a current which is passed through the PIN diode;
• and
• a current output step of outputting, by the DA converter, a corrected analog current as the control current so that a logarithmic value of the amount of attenuation of the high frequency signal by the PIN diode is allowed to change linearly to the digital data.