Loading...

Single-VCO multi-band DTV frequency synthesizer with a divide-by-3 frequency divider for quadrature signal generation

Saeedi, S ; Sharif University of Technology

1714 Viewed
  1. Type of Document: Article
  2. DOI: 10.1007/s10470-009-9437-0
  3. Abstract:
  4. A multi-band frequency synthesizer for In-phase and Quadrature (I/Q) LO signal generation in Digital TV tuners is presented. Using divisor numbers other than powers of 2 (2 n ) for quadrature generation, reduces the required frequency range of the VCO, hence the number of VCO circuits, in multi-band frequency synthesizers. In the proposed synthesizer, VHF, UHF and L-band frequencies are covered with only one VCO. This is achieved by using a novel divide-by-3 circuit which produces precise I/Q LO signals. The VCO tuning range in this design is 2,400-3,632 MHz which is covered by a 6-bit switched-capacitor bank. A fast adaptive frequency calibration block selects the closest VCO frequency to the target frequency by setting the coarse-tuning code prior to the start of phase lock. A programmable charge pump is used to reduce variations in PLL characteristics over the frequency range. The synthesizer has been fabricated in a 0.18 μm CMOS technology and the die area is 1.7 × 1.6 mm2. It consumes 27 mA from a 1.8 V power supply. Measurement results show operation of the proposed divide-by-3 circuit over the entire VCO frequency range. The synthesizer quadrature output phase noise for UHF and VHF bands is <-131dBc/Hz at 1.45 MHz offset
  5. Keywords:
  6. Digital TV ; Frequency synthesizer ; Adaptive frequency calibrations ; CMOS technology ; Die area ; Digital TV ; Digital TV tuner ; Divide-by-3 circuit ; Frequency dividers ; Frequency ranges ; In-phase ; L-band frequencies ; Measurement results ; Multiband ; Phase lock ; Power supply ; Programmable charge pumps ; Quadrature generation ; Quadrature outputs ; Quadrature signal generation ; Reduce variation ; Signal generation ; Switched capacitor ; Target frequencies ; Tuning ranges ; VCO circuits ; VCO frequency ; Capacitors ; CMOS integrated circuits ; Frequency synthesizers ; Pumps ; Tuning ; Variable frequency oscillators ; Digital television
  7. Source: Analog Integrated Circuits and Signal Processing ; Volume 64, Issue 2 , 2010 , Pages 103-113 ; 09251030 (ISSN)
  8. URL: http://link.springer.com/article/10.1007/s10470-009-9437-0