A constant-envelope, continuous phase modulation architecture is presented in which a sigma-delta modulator is combined with an open-loop modulator. Compared to existing architectures, Σ∆ based open-loop modulation can be implemented with minimal analog circuitry. The architecture is demonstrated with a discrete implementation performing frequency modulation at a carrier frequency of 120 MHz. B...

This paper brief the use of very high precision Noise shaping sigma delta modulation techniques for high applications that require a signal-to-noise ratio and high resolution. A continuous-time delta-sigma A/D modulator with OSR of 40, signal bandwidth of 1.5625 MHz and clocked at 500MHz is implemented. This achieves 78 dB SNR and 12 bits of resolution.

A weakly nonlinear oscillator of natural frequency omega(0) and damping ratio delta is driven by an amplitude-modulated force of dimensionless amplitude epsilon, carrier frequency omega, and modulation frequency omega(1). Each of (omega - omega(0))/omega(0), omega(1)/omega(0), and delta is O(epsilon(2/3)) as epsilon --> 0. The response in this resonant neighborhood is a slowly modulated sine wa...

A third-order sigma-delta (Σ -Δ ) modulator implementation in a Digital Power Amplifier is presented in this paper. The operation is obtained by using a novel combination of architectural features, proper circuit structure selections, specific clocking strategies, and efficient circuit optimization algorithms. Measurement results from fabricated CMOS chip prototypes show a good match with simul...

|The high-order modulator is an appropriate approach for high-bandwidth, high-resolution A/D conversion. However, non-ideal e ects such as the nite opamp gain and the capacitor mismatch have great impacts on its performance at a low oversampling ratio. To achieve greater performance under the inevitable non-ideal e ects, we explore several multiple-bit schemes, based on our CIQE high-order arch...

In order to eliminate the use of operational amplifiers (opamps) in sampled-data systems and thus avoid several delicate tradeoffs involved with their design, a new class of switched-capacitor circuits based on comparators was reported. The novelty of this comparator-based switched-capacitor (CBSC) design method is the detection of a virtual ground condition rather than forcing it through feedb...

Force control deficits have been repeatedly documented in autism spectrum disorder (ASD). They are associated with worse social and daily living skill impairments in patients suggesting that developing a more mechanistic understanding of the central and peripheral processes that cause them may help guide the development of treatments that improve multiple outcomes in ASD. The neuromuscular mech...