An improved pseudo-exponential, pseudo-logarithmic circuit

In this paper a useful pseudo-exponential and pseudo-logarithmic circuit is proposed that offers improved performance compared to a current-conveyorbased design. The circuit employs two operational amplifiers and several resistors and mimics the exponential and logarithmic functions over predefined ranges. Control of the pseudo-functions is achieved by a single resistance, which may be digitally switched or implemented by tunable transconductors. Measured results using digitally switched resistors and commercially available components demonstrate the versatility of the circuit for audio/video applications.