Numerical and theoretical analysis on voltage and time domain dynamic range of scaled CMOS circuits
It is believed that the time-domain resolution of a digital signal edge transition is superior to the voltage resolution of an analog signal in advanced CMOS processes[1], [2]. The reasoning behind this is that operating voltage has been reducing, making the signal more vulnerable to noise power due to scaling. On the other hand, in time domain, scaling has resulted to increase in frequency and therefore design of faster circuits, while also contributing to reduction of jitter. However, this is a concept that has not yet been quantitatively examined. This paper aims at verifying the effectiveness of the time-domain circuits over voltage-domain circuits in terms of their dynamic range performances by simulations as well as by theoretical analysis, especially in the scaled nano-meter processes. It has been shown that for a given technology the time domain dynamic range is superior to the voltage domain dynamic range by a factor of (ωT /B)2 where ωT is the unity gain frequency and B is the bandwidth.
Predicting noise and jitter in CMOS inverters
Jitter in CMOS technologies depend on several physical and design parameters, which are expected to change with scaling. Also, some parameters will have to change (by the introduction of enhancement techniques) in order to meet the desired performance goals for each new generation. The impact of each one of these parameters is here evaluated in order to give some insight on the jitter generation, amplification and coupling phenomena in actual and future designs. The work is based on AMS (0.8 um and 0.35 um) and UMC (180 nm and 130 nm) models for high performance, minimum sized transistors. Also, data from ITRS has been used to predict jitter dependency on the various parameters in deep-submicron CMOS generations.
ANALYSIS OF BOLT′S ANCHORING QUALITY BASED ON WAVELET NEURAL NETWORK
The dynamic response of bolt achieved by impact-echo method can be effected easily by some factors.It′s difficult to classify bolt′s anchoring quality according to the dynamic response of bolt.In this paper,a new analytical method of bolt′s dynamic response is put forward.The new analytical method combing with advantages of wavelet analysis and artificial neural network is presented.Firstly,the dynamic response of bolt by numerical simulation software FLAC3D is obtained.Secondlyt,he features are extracted from the dynamic response of bolt by wavelet analysis.Thirdlyt,hese features are fed into the artificial neural network for training.Finallyt,his artificial neural network to classify the bolt′s anchoring quality intelligent according to the dynamic response of bolt is employed.In order to validate this new analytical method,some practical signals of bolt′s dynamic response are used for the test.The results indicate that the new analytical method is practicable.