Some New Operational Transresistance Amplifier Based Sinusoidal_Square Waveform Generators

Abstract

Waveform generators have wide range of applications in numerous electronic devices, including electronic instruments, measurement systems, telecommunications, power conversion control circuits and signal processing applications. Several waveform generator circuits have existed in the literature based on operational amplifier (op-amp) as a main active element. However, these circuits are not able to operate at high frequency due to fixed gain bandwidth product and less slew rate. newlineTo conquer the above disadvantages several circuits have been presented in the literature based on current-mode devices. When wide bandwidth, low power consumption and low voltage operation are needed simultaneously, current mode devices are preferred rather than voltage mode devices. Current mode circuits feature the advantage of high bandwidth, better linearity, larger dynamic range and non-interference between the gain and bandwidth. newlineIn recent past, an active current mode device operational transresistance amplifier (OTRA) has made considerable attention of the analog IC designers. OTRA is a three terminal active device. Several implementations have emerged using OTRA such as Voltage Gain Amplifiers (VGAs), filters, Proportional Integral and Derivative (PID) controllers, analogue multiplier, immitance simulators, oscillators and waveform generators. newlineSinusoidal waveform generators with independent control of condition of oscillation and frequency of oscillation play an important role in communications and signal processing application. It has also been seen that the OTRA is very useful as an analogue building block and receiving regular attention in waveform generators, oscillators, and design of amplifiers and filters. The OTRA provides a constant bandwidth virtually independent of the gain. Characterized by low input and output impedances, it leads to circuits that are insensitive to stray capacitances, providing current processing at the input terminal which are virtually grounded. newline newline