An 8-PSK receiver using LNA & SRO: Design and mathematical analysis

Analysis and design of 8-PSK low power Receiver using an Integrated Low-Noise Amplifier (LNA) and Super-Regenerative Oscillator (SRO) with Digital Detection Technique. The main motivation of doing this work lies in the fact that it consumes less power and the design is simple and gives significant amount of gain. The major power saving feature in this design is Super-Regenerative Oscillator that regenerates the incoming RF signal to higher level that eliminates the use of active mixer. The design features a technique of merging the Low-Noise Amplifier block inside the SRO block for current reuse which is another power saving factor of the design. The ideation lies in the concept of reception of modulated signals using Super-Regeneration that was invented by Armstrong in 1992 and taken over by his another invention of heterodyne receiver. In wireless networks the wireless nodes are in need of such a transceiver that consumes least power for their long lasting life and here the idea of super regeneration is used. The major advantage of the design is its power saving feature and simplicity in design which can be viewed from the fact that it eliminates the use of Local Oscillators, Phase Locked Loop and Analog-to-Digital Converter (ADC) in the receiver circuit.;Majority of the research work in recent and the past has been centered on using Super-Regenerative Receiver (SRR) to receive OOK modulated signals, FSK and PSK modulated signals and also BFSK modulated signals. The classical OOK detection was performed by asynchronous switching of the SRO by a quench signal that has frequency higher than data rate. Here the quench signal is nothing else but the oscillator's bias current. For the purpose of quenching the oscillator current is switched ON and OFF periodically. The receiver is operating in the frequency range of 402-405 MHz (MICS Band) in which most of the short distance low power wireless application takes effect. The power consumption is about 175 muW for an input of -80 dBm at a rate of 4Mbps. The design made use of 0.12 mum CMOS technology. The design of the proposed transceiver is based on the property of phase preservation of the input RF signal when passed through the combination of LNA and SRO circuit. Since the phase information of the SRO output is preserved, it is exploited by the digital detection scheme used for 8-PSK modulated signals.;A theory of Super-Regenerative Reception from a general point of view has been obtained. I am raising an analytic study based on a general block diagram of the receiver that studies not only narrow-band, but a wider selection of input signals. Beginning from the proposed model of receiver, the differential equation that describe the operation of receiver in linear mode is deduced and solved. As a novelty, the set of equations have been produced that governs the detection of not only QPSK and 8-PSK modulated signals but also any M-PSK modulated signals.