Sumit A. Talwalkar

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This paper presents the analogue of the time or frequency scaling theorem of continuous time/frequency Fourier Transform (FT) to the realm of Discrete Fourier Transform (DFT). The scaling property applies to scaling by integers which are relatively prime to the length of the DFT. The time reversal property of DFT is identified as a special case of this(More)
In 2007 we reported a flexible integrated circuit transceiver operating from 100 MHz to 2.5 GHz with continuous coverage over that range [1-2]. A new version of the chip is now available with improved performance and significant new features. Notable performance improvements include operation up to 4 GHz using the on-chip direct digital synthesizers (DDS)(More)
Dithering is used in many discrete to continuous value conversion functions to provide an effective fractional value. This paper reviews the application of dither to a digital-to-time converter (DTC) based digital synthesizer suitable for many common wireless communication systems. Measurements of a 90 nm CMOS implementation using a 5 bit DTC show extension(More)
This paper reports a flexible direct digital modulation based low power transmitter in 90 nm CMOS that supports constant-envelope modulation using phase or frequency modulation for carrier frequencies from 100 MHz to 2.5 GHz. For rectangular filtered 8-PSK modulation from 1 K symbol/s to 20 M symbol/s the RMS phase error is less than 4 deg. Frequency(More)
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