Relationship between ADC performance and requirements of digital-IF receiver for WCDMA base-station

The recent rapid development of digital wireless systems has led to the need for multistandard, multichannel radiofrequency (RF) transceivers. The paper presents the relationship between the performance of a bandpass-sampling analog-to-digital converter (ADC) and the requirements of a digital intermediate-frequency receiver for a wideband code-division multiple-access (WCDMA) base-station. As such, the ADC signal-to-noise ratio (SNR), the derivation of the receiver sensitivity using the SNR/spurious free dynamic range (SFDR) of the ADC, the effect of the ADC clock jitter and receiver linearity, plus the relationship between the receiver IF and the ADC sampling frequency are all analyzed. As a result, when a WCDMA base-station receiver has a data rate of 12.2 kbps, bit error rate (BER) of 0.001, and channel index, k, of 5 (sampling frequency of 122.88 MHz and IF of 92.16 MHz), the performance of a bandpass-sampling ADC was analytically determined to require a resolution of 14 bits or more, SNR of 66.6 dB or more, SFDR of 86.5 dBc or more, and total jitter of 0.2 ps or less, including internal ADC jitters and clock jitters.