A Fully Integrated Discrete-Time Superheterodyne Receiver

Design of configurable superhetrodyne receiver for wireless medical applications

OVERVIEW

The zero/low intermediate frequency (IF) receiver (RX) architecture has enabled full CMOS integration. As the technology scales and wireless standards become ever more challenging, the issues related to time-varying dc offsets, the second-order nonlinearity, and flicker noise become more critical. In the existing paper a new architecture of a superheterodyne RX that attempts to avoid the issues related to time-varying dc offsets. By exploiting discrete-time (DT) operation and using only switches, capacitors, and inverter-based gm-stages as building blocks, the architecture becomes amenable to further scaling. Full integration is achieved by employing a cascade of four complex-valued passive switched-cap-based band pass filters sampled at 4× of the local oscillator rate that perform IF image rejection. Channel selection is achieved through an equivalent of the seventh-order filtering. A new twofold noise-canceling low-noise transconductance amplifier is proposed. Frequency domain analysis of the RX is presented by the proposed DT model. The RX is wideband and covers 0.4–2.9 GHz with a noise figure of 2.9–4 dB. It is implemented in 65-nm CMOS and consumes 48–79 mW.

Existing System

In the existing paper a new architecture of a superheterodyne RX that attempts to avoid the issues related to time-varying dc offsets. By exploiting discrete-time (DT) operation and using only switches, capacitors, and inverter-based gm-stages as building blocks, the architecture becomes amenable to further scaling. Full integration is achieved by employing a cascade of four complex-valued passive switched-cap-based band pass filters sampled at 4× of the local oscillator rate that perform IF image rejection. Channel selection is achieved through an equivalent of the seventh-order filtering.

Proposed System

In the proposed system a configurable VLSI design architecture is being designed in which the superheterodyne receiver is designed purely in digital manner to handle multiple frequency of operation. The design used at various medical applications nowadays medical electronics inventments are more precise and requires more challenging configurations to be done at minimum time for various medical analysis of disease etc The proposed system is used to generate such variable outputs of audio frequencies used at medical equipments.