Title :
An open-loop octave-phase local-oscillator generator with high-precision correlated phases for VHF/UHF mobile-TV tuners
Author :
Un, Ka-Fai ; Mak, Pui-In ; Martins, R.P.
Author_Institution :
Analog & Mixed-Signal VLSI Lab., Univ. of Macau, Macao, China
Abstract :
An octave-phase local-oscillator (LO) generator for 170-to-860-MHz mobile-TV tuners is described. It is intended to incorporate with a polyphase mixer scheme for rejecting the 3rd and 5th harmonics of the LO that is critical for wideband reception. The circuit is structured by a cascade of 7 inverter-based phase correctors to generate a set of LO signals with octave phases in an open-loop formation, resulting in 4times relaxation of the synthesizer´s operating frequency when comparing with the conventional closed-loop form that requires the use of a div-by-4 frequency divider. Optimized in a 90-nm CMOS process, the achieved phase precisions are plusmn0.8deg in VHF III (170 to 245 MHz) band and UHF (470 to 860 MHz) band while drawing 2.3 to 5.1 mA from a 1-V supply.
Keywords :
UHF oscillators; VHF oscillators; mobile television; phase locked oscillators; CMOS process; LO generator; UHF mobile-TV tuners; VHF mobile-TV tuners; current 2.3 mA to 5.1 mA; frequency 170 MHz to 245 MHz; frequency 470 MHz to 860 MHz; high-precision correlated phases; inverter-based phase correctors; open-loop octave-phase local-oscillator generator; polyphase mixer scheme; size 90 nm; voltage 1 V; wideband reception; Circuits; Frequency conversion; Frequency synthesizers; Hardware; Phase locked loops; Signal generators; Tuners; Very large scale integration; Voltage-controlled oscillators; Wideband;
Conference_Titel :
Circuits and Systems, 2009. ISCAS 2009. IEEE International Symposium on
Conference_Location :
Taipei
Print_ISBN :
978-1-4244-3827-3
Electronic_ISBN :
978-1-4244-3828-0
DOI :
10.1109/ISCAS.2009.5117778