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

Abstract

The recent rapid development of digital wireless systems has led to the need for multistandard, multichannel radio-frequency (RF) transceivers. This 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 wide-band code-division multiple-access (WCDMA) base station. As such, the ADC signal-to-noise ratio (SNR), the derivation of 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 of five (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.

Design of a fully integrated receiver analog baseband chain for 2.4-GHz ZigBee applications

“…The integral non-linearity (INL) and differential non-linearity (DNL) are required less than 1 LSB to guarantee the monotonicity. Furthermore, the loss of receiver signal-to-noise ratio (SNR) contributed by ADC can be acceptable if the SNR of the ADC is 20 dB higher than the SNR due to the thermal noise component [10]. Considering the receiver noise power of À 90.5 dBm and the processing gain of 9 dB, the required SNR for ADC is 16.5 dB which means the required effective number of bits (ENOB) is 3 bits.…”