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This work proposes a simple method to enhance amplitude stability in Pierce crystal oscillator. The method is based on a modification of the conventional Pierce oscillator. The proposed topology is all-analog, yet it does not use an amplifier-based feedback loop for amplitude control, hence, it saves power, reduces complexity, and layout area. The proposed method does not adversely impact oscillator's phase noise, and gives good amplitude control results against process, voltage, and temperature (PVT) variations. An example design for a 40 MHz Pierce crystal oscillator is implemented in a standard 0.13 m CMOS technology and compared to conventional Pierce oscillator results. The current consumption of the oscillator core is 500 A off 1.2 V supply. The proposed method is extensible to other CMOS VCOs, including Giga-Hertz ones, to reduce design margins on VCO gain.

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The jamming analysis transmission selection (JATS) sub-system is used in radar systems to detect and avoid the jammed frequencies in the available operating bandwidth during signal transmission and reception. The available time to measure the desired frequency spectrum and select the non-jammed frequency for transmission is very limited. A novel fast time (FAT) technique that measures the channel spectrum, detects the jamming sub-band and selects the non-jammed frequency for radar system transmission in real time is proposed. A JATS sub-system has been designed, simulated, fabricated and implemented based on FAT technique to verify the idea. The novel FAT technique utilizes time-domain analysis instead of the well-known fast Fourier transform (FFT) used in conventional JATS sub-systems. Therefore, the proposed fast time jamming analysis transmission selection (FAT-JATS) sub-system outperforms other reported JATS sub-systems as it uses less FPGA resources, avoids time-delay occurred due to complex FFT calculations and enhances the real time operation. This makes the proposed technique an excellent candidate for JATS sub-systems.