Towards flexible parallel sigma delta modulator for software defined radio receiver

Abstract

A novel frequency band decomposition architecture based on a single-bit 4 th order sigma delta modulators and intended for a software defined radio receiver is presented in this paper. The parallel designed architecture is flexible with parallel programmable branches. Synthesis results prove that this architecture satisfies the multistandard receiver specifications without the use of automatic gain control circuit. Nevertheless, system level analysis of the mixed baseband architecture using a single passive anti-aliasing filter has revealed adjacent branch interference problems. A design specification for a non-unitary signal transfer function for sigma delta modulators is proposed to cover interferences of adjacent branches.

Phase mismatch study and correction of a parallel FBD ΣΔ ADC for SDR receiver

“…Accordingly, the authors take advantage of FBD architecture to design a flexible parallel ∆ ADC intended for an SDR receiver that processes E-GSM, UMTS and IEEE802.11a communication signals [6]. The FBD Σ∆-based architecture is based on a frequency decomposition of the input signal.…”

“…The novelties in this designed FBD architecture are that the sub-bandwidths of the parallel branches are different and that the sampling frequencies are modified from one standard to another [6]. The FBD design is composed of six programmable branches based on discrete-time (DT) single-bit quantizer Σ∆ modulators [6].…”

“…The FBD design is composed of six programmable branches based on discrete-time (DT) single-bit quantizer Σ∆ modulators [6]. The first branch uses a low-pass (LP) 4 th order Σ∆ modulator and the other five parallel branches are composed of band-pass (BP) 8 th order Σ∆ modulators [6].…”

“…The FBD design is composed of six programmable branches based on discrete-time (DT) single-bit quantizer Σ∆ modulators [6]. The first branch uses a low-pass (LP) 4 th order Σ∆ modulator and the other five parallel branches are composed of band-pass (BP) 8 th order Σ∆ modulators [6]. According to the selected standard, only some branches of the FBD architecture are active with adequate operating sub-bandwidths and sampling frequency regarding a frequency division plan [6].…”

“…The first branch uses a low-pass (LP) 4 th order Σ∆ modulator and the other five parallel branches are composed of band-pass (BP) 8 th order Σ∆ modulators [6]. According to the selected standard, only some branches of the FBD architecture are active with adequate operating sub-bandwidths and sampling frequency regarding a frequency division plan [6]. Consequently, the designed architecture is programmable, flexible and optimized.…”