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In this paper, a novel $$\pm $$ 0.8V current differencing transconductance amplifier (CDTA) with programmable and tunable ability is proposed and analyzed. The digitally programmable CDTA is built around a lot of programmable current mirror arrays and three linear tunable transconductors, which contains separate analog and digital tuning feature. Moreover, a CDTA-based general sinusoidal signal generator circuit with two fixed-value capacitors and two grounded resistors is presented here. The generator circuit can be configured to perform the following signal modulation techniques: amplitude modulation, frequency modulation, amplitude shift keying, frequency shift keying, phase shift keying, and quadrature amplitude modulation. Cadence Virtuoso Analog Design Environment using GlobalFoundries' 0.18 um CMOS process is used to develop the generator circuit and verify the theory by the post-layout simulations. [ABSTRACT FROM AUTHOR]

In this paper, a new active device, current differencing cascaded transconductance amplifier (CDCTA), has been presented. The proposed CDCTA simplifies the design of the current-mode filter circuit considerably, especially the design of high-order filter. Moreover, a current-mode nth-order filter based on the CDCTA is proposed in the paper. The proposed circuit, which adopts only an active component and n grounded capacitors, contains minimal active component and passive one. It enjoys the simple configuration and is suitable for integrated circuit (IC) fabrication. PSpice simulations for current-mode third-order filter based on this structure have also been conducted, and the results are in good agreement with the theoretical analysis. The influences of the CDCTA non-idealities are also discussed. [ABSTRACT FROM AUTHOR]