A passive bias temperature compensation module for silicon photomultiplier, avalanche photodiodes and similar photodetectors that possess a moderately linear temperature coefficient of gain and that may be compensated by varying an applied bias voltage. The module includes an electrical circuit and a method for determining component values to provide a constant voltage source to stabilize the gain of one or more photodetector devices. A temperature sensor in the module is held in close thermal contact with the photodetector and a filter capacitor is electrically close to the photodetector. The module is based on the concept of temperature sensitive voltage division which is applicable to situations in which large numbers of photodetectors must be gain-compensated for temperature variations over a wide range while maintaining excellent gain matching. The passive bias temperature compensation method enables multiple photodetectors to share a single constant voltage supply without loss of matching performance.

A thermistor drive circuit includes a plurality of driving resistors, at least one current correction resistor, a voltage measurement unit and a controller. The driving resistors are selectively connected to a thermistor for correcting a temperature characteristic of the thermistor whose resistance value changes in accordance with a temperature to be detected. The current correction resistor is selectively connected between a power supply and a ground. The voltage measurement unit measures a terminal voltage of the thermistor. The controller switches connection states of the driving resistors according to the terminal voltage. When switching the connection states of the driving resistors, the controller also switches a connection state of the current correction resistor to suppress a fluctuation of a power supply current before and after the switching of the connection states of the driving resistors.

A passive bias temperature compensation module for silicon photomultiplier, avalanche photodiodes and similar photodetectors that possess a moderately linear temperature coefficient of gain and that may be compensated by varying an applied bias voltage. The module includes an electrical circuit and a method for determining component values to provide a constant voltage source to stabilize the gain of one or more photodetector devices. A temperature sensor in the module is held in close thermal contact with the photodetector and a filter capacitor is electrically close to the photodetector. The module is based on the concept of temperature sensitive voltage division which is applicable to situations in which large numbers of photodetectors must be gain-compensated for temperature variations over a wide range while maintaining excellent gain matching. The passive bias temperature compensation method enables multiple photodetectors to share a single constant voltage supply without loss of matching performance.

A wireless receiver includes an RSSI generation circuit that obtains RSSI output corresponding to a carrier strength level of a received RF signal; a lookup table from which a threshold value corresponding to temperature information from a temperature sensor is read based on the temperature information; a comparison circuit that generates comparison output when the RSSI output is below the threshold value read from the lookup table, in which the threshold value is one input, and the RSSI output from the RSSI generation circuit is the other input; and a muting circuit that closes a signal line of an audio signal demodulated from the RF signal, and cuts off output of the audio signal, based on the comparison output from the comparison circuit. The above configuration enables the wireless receiver to eliminate fluctuation of a reception reaching distance relative to temperature change, and ensure stable mute operation.

A wireless receiver includes an RSSI generation circuit that obtains RSSI output corresponding to a carrier strength level of a received RF signal; a lookup table from which a threshold value corresponding to temperature information from a temperature sensor is read based on the temperature information; a comparison circuit that generates comparison output when the RSSI output is below the threshold value read from the lookup table, in which the threshold value is one input, and the RSSI output from the RSSI generation circuit is the other input; and a muting circuit that closes a signal line of an audio signal demodulated from the RF signal, and cuts off output of the audio signal, based on the comparison output from the comparison circuit. The above configuration enables the wireless receiver to eliminate fluctuation of a reception reaching distance relative to temperature change, and ensure stable mute operation.