New type of analogue multiplier with wide dynamic range

For reasons which are discussed in this letter, the dynamic range of existing transconductance-type analogue multipliers falls short of that imposed by device limitations when they are used in a constant-output mode. It is shown that, by employing a new type of circuit in the feedback path of an operational amplifier, a dynamic range of 86 dB can be obtained over a control range of 30 dB with less than 0.25% departure from linearity.