Low-complexity Chebyshev High-pass Filter based on OTA-C

Abstract

This work presents a new Chebyshev ladder high-pass filter based on operational transconductance amplifier (OTA) based differentiators. Lossy and Lossless differentiators based on the OTA-C technique are deployed as the main sub-circuits. The Chebyshev ladder high-pass filter is transformed from a low-pass RLC prototype by using the network transformation method. The signal flow graph (SFG) and third-order RLC prototype are used to synthesis the active high-pass filter. The final SFG functions can be directly replaced by OTA-C current-mode differentiators. Due to the proposed structure of the high-pass filter contains only 6 OTA(s) and 3 grounded capacitors that resulting in the low-complexity and low components count. The frequency responses of the proposed filter can be electronically tuned between 200kHz and 8MHz by varying the bias currents (IB) from 3 μ A to 300 μ A. The proposed filter response good agreement with the response of the RLC prototype. PSpice simulation results are carried out to verify the filter performances.