Transducer and related circuitry

Abstract

In this transducer, for converting an analog input signal into an analog output signal whose level corresponds to the level of the analog input signal, there are included: an A/D converter for converting the analog input signal into a digital signal; an input device comprising a plurality of switches; an upper limit setting means for setting an upper limit value for the analog input signal, according to operation of the switches; a lower limit setting means for setting a lower limit value for the analog input signal, according to operation of the switches; a storage device, for storing a current value of the digital signal output by the A/D converter; a comparison means for comparing the current value of the digital signal output by the A/D converter as converted from the analog input signal, and the upper limit value and the lower limit value, all of which are stored in the storage device; an output means for producing an output when the comparison executed by the comparison means indicates that the current value of the digital signal output by the A/D converter as converted from the analog input signal has exceeded the upper limit value, or has dropped below the lower limit value; and a D/A converter for converting the digital signal output by the A/D converter as converted from the analog input signal into an analog output signal whose level corresponds to the level of the analog input signal. Variations on this theme are also disclosed.