AUDIO ADC FOR MOBILE APPLICATIONS FEATURING A NOVEL GAIN CONTROL TECHNIQUE, DITHERING INSERTION AND IDLE TONES SHIFTING

Francesco Rizzo, Shyam Somayajula, Domenico Zito, Roberto Saletti, Rolf Becker

Abstract

One of the main parts in the audio uplink path for mobile transceivers is an Analog-to-Digital- Converter (ADC) operating in the audio band. The ADC is usually preceded or followed by a Programmable Gain Amplifier (PGA) which allows, together with a digital signal processor, the gain control of the audio transmit path. Changing the gain is an operation which can lead to artifacts as it inserts discontinuities in the audio wave which behave as distortion sources. This paper describes a novel technique for embedding the gain change in the ADC body. In particular, this technique allows a smooth gain change directly in a sigma delta ADC reducing distortions effects and replacing the programmable gain amplifier in the uplink chain, hence allowing performance enhancement and area and power reduction of the overall integrated circuit (IC). In addition, possible implementations of dithering at a minimum area overhead are discussed.

Download

IMEKO-IWADC-2011-34.pdf

DOI

-

IMEKO TC

TC4 - Measurement of Electrical Quantities

Back to the proceedings