09-05-2012, 03:31 PM
Global Positioning System
FULLY_INTEGRATED_CMOS_GPS_R.pdf (Size: 378.36 KB / Downloads: 52)
INTRODUCTION
GLOBAL Positioning System (GPS) receivers for the consumer
market require solutions that are compact, cheap, and low power.
Manufacturers of cellular telephones, portable computers, watches, and other
mobile devices are looking for ways to embed GPS into their products. Thus,
there is a strong motivation to provide highly integrated solutions at the lowest
possible power consumption. GPS radios consist of a front-end and a digital
baseband section incorporating a digital processor. While for the baseband
processor, cost-reduction reasons dictate the use of the most dense digital
CMOS technology, for the front-end, the best option in terms of power
consumption is a SiGe BiCMOS technology.
ARCHITECTURE AND SPECIFICATIONS
The GPS signal code is a direct-sequence spread spectrum, and the type
of spread spectrum employed by GPS is known as binary phase-shift keying
direct-sequence spread spectrum (BPSK DSSS). In a spread-spectrum system,
data are modulated onto the carrier such that the transmitted signal has a larger
bandwidth than the information rate of the data. The term “direct sequence” is
used when the spreading of the spectrum is accomplished by phase modulation
of the carrier.
CHIP DESIGN
As stated, the overall design has been geared to a high level of
integration and reduction of silicon area at the lowest possible power
consumption. Below, the detailed design choices in the various sections are
described.
RF Section
The LNA has been designed to have a very low noise since it sets a lower
bound for the total receiver sensitivity. A high voltage gain is necessary to
sufficiently reduce the noise contribution of the following mixers.
FULLY_INTEGRATED_CMOS_GPS_R.pdf (Size: 378.36 KB / Downloads: 52)
INTRODUCTION
GLOBAL Positioning System (GPS) receivers for the consumer
market require solutions that are compact, cheap, and low power.
Manufacturers of cellular telephones, portable computers, watches, and other
mobile devices are looking for ways to embed GPS into their products. Thus,
there is a strong motivation to provide highly integrated solutions at the lowest
possible power consumption. GPS radios consist of a front-end and a digital
baseband section incorporating a digital processor. While for the baseband
processor, cost-reduction reasons dictate the use of the most dense digital
CMOS technology, for the front-end, the best option in terms of power
consumption is a SiGe BiCMOS technology.
ARCHITECTURE AND SPECIFICATIONS
The GPS signal code is a direct-sequence spread spectrum, and the type
of spread spectrum employed by GPS is known as binary phase-shift keying
direct-sequence spread spectrum (BPSK DSSS). In a spread-spectrum system,
data are modulated onto the carrier such that the transmitted signal has a larger
bandwidth than the information rate of the data. The term “direct sequence” is
used when the spreading of the spectrum is accomplished by phase modulation
of the carrier.
CHIP DESIGN
As stated, the overall design has been geared to a high level of
integration and reduction of silicon area at the lowest possible power
consumption. Below, the detailed design choices in the various sections are
described.
RF Section
The LNA has been designed to have a very low noise since it sets a lower
bound for the total receiver sensitivity. A high voltage gain is necessary to
sufficiently reduce the noise contribution of the following mixers.