The Implementation Of One-dimension Wavelet Transform Through Hybrid Of Analog And Digital Circuit

The wavelet transform is no only used in the protection of traveling wave in the power system, but also having many applications in the acoustics . graph and communication. It is also the focus of many subject. It is regretted that most of wavelet transform is based on discrete-time system. The working pattern of discrete-time system is flexible, but it need A/D and D/A, which make that system work slowly. Analysis the virtue and shortcoming of these two system, this paper put forward a way to achieve wavelet transform through hybrid of analog and digital circuit.First ,this paper discuss the virtue and shortcoming of the Fourie transform Gabor transform and wavelet transform .Get out the result why we choose the wavelet transform.Second, we discuss the wavelet transform deeply from math and multi-rate sampling, getting the relations of them and how to get mother wavelet correctly. In order to simplify the designation of circuit, we use complex demodulation technique, it can let us design low pass filter instead of bandpass filter. We make use of DDS to get different central frequency, comparing to use VCO and PLL through analog IC, it simplified the designation of circuits, improved the speed of design.Third, the digital filter is commonly used in the wavelet transform in the past. Its shortcoming is that the speed of signal process is slow because of A/D. Analog circuit don't need A/D, so its speed can get very high., having great advantage. The paper bring out a way using analog filter to achieve a group of low pass filter which are needed by the wavelet transform. In the analog IC the achievement is difficult, though we use active filter to achieve the goal. In the designation of active filter, the operational amplifier is very important; we will particularly discuss the designation of the op amp. At last we get the circuit, and simulating the circuit. The Gaussian filter has a good time-frequency rate, we choose Gaussian filter as mother wavelet. We design the circuit and get the simulation result.At last, we get a completely designation of the implementation of an analogwavelet transform through hybrid of analog and digital circuit. This circuit include DDS which generate central frequency, five pair of low pass filter, 20 multipliers, and an adder. We finish the process from decompose to reconstruct, achieving the goal that we want.