Improved method for measuring frequency ratios in GSM mobile phones

The principle of operation of the ubiquitous low-cost digital circuits for frequency measurement appears to have remained unchanged for decades. In applications with very high accuracy requirements, such as in GSM mobile phones, these conventional solutions can lead to excessive measurement periods with detrimental effect on the stand-by time. In this paper, we present a novel frequency measurement technique which is based on regression algorithms. Experiments with a hardware implementation prove that the crucial product of measurement error and measurement period can be reduced by orders of magnitude compared to conventional solutions while the slight extension of the digital circuitry is virtually for free.