Massage machine and physiological quantity measuring circuit for use in the machine

A physiological quantity control and measuring circuit for a massage machine, the circuit detecting a physiological quantity of the person massaged and controlling the massage operation of the machine based on variations in the physiological quantity, the measuring circuit comprising:

• at least one sensor, sensing a single physiological quantity:
• a detection and signal processing circuit, for producing physiological quantity data based on a signal obtained from the sensor, comprising a plurality of signal converters each adapted to receive an input signal from the sensor and deliver a respective output signal corresponding to the single physiological quantity,
• the signal converters exhibiting respective different signal conversion characteristics which are different in the relationship of the output signal to the input signal, the different signal conversion characteristics overlapping each other in an input range of the input signal,
• the detection and signal processing circuit being operable to produce data to control the massage operation based on the output signal, regardless of how many of the signal converters are used to convert the input signal into the output signal.