Title :
A 1.3-GHz IF digitizer using a 4th-order continuous-time bandpass ΔΣ modulator
Author :
Kaplan, T. ; Cruz-Albrecht, Jose ; Mokhtari, Mehran ; Matthews, Dave ; Jensen, Joe ; Chang, M. Frank
Author_Institution :
Hughes Res. Labs., Malibu, CA, USA
Abstract :
We present a 4th-order, 3-bit, 4.3 GHz continuous-time bandpass ΔΣ modulator (CT-DSM) that can directly digitize a 1.3-GHz IF signal. We used the impulse-invariant transform to design the CT-DSM, which has a similar NTF (noise transfer function) as an idealized discrete-time modulator despite up to 1.6 clock delays in its feedback loop paths. The part was fabricated using InP HBT technology, and has a measured SNDR of 39 dB in a 200 MHz bandwidth.
Keywords :
UHF integrated circuits; analogue-digital conversion; bipolar integrated circuits; circuit feedback; delta-sigma modulation; transfer functions; 1.3 GHz; 200 MHz; 4.3 GHz; CT-DSM; HBT technology; IF digitizer; InP; NTF; continuous-time bandpass ΔΣ modulator; feedback loop path clock delays; impulse-invariant transform; noise transfer function; Bandwidth; Clocks; Delay; Delta modulation; Digital modulation; Discrete transforms; Feedback loop; Heterojunction bipolar transistors; Indium phosphide; Transfer functions;
Conference_Titel :
Custom Integrated Circuits Conference, 2003. Proceedings of the IEEE 2003
Print_ISBN :
0-7803-7842-3
DOI :
10.1109/CICC.2003.1249375
