Analog wavelet transform circuitry

• US 5,495,554 A
• Filed: 01/08/1993
• Issued: 02/27/1996
• Est. Priority Date: 01/08/1993
• Status: Expired due to Term

• Current Assignee: IXYS Intl Limited (Littelfuse Incorporated)
• Original Assignee: ZiLOG Incorporated (Littelfuse Incorporated)
• Inventors: Edwards, R. Timothy, Godfrey, Michael D.
• Primary Examiner(s): MacDonald, Allen R.
• Assistant Examiner(s): Dorvil, Richemond
• Application Number:
  US08/001,802
• Time in Patent Office: 1,145 Days
• Field of Search: 395/2, 395/2.1, 395/2.14, 395/2.15, 395/2.16, 395/2.36, 381/48, 381/49, 381/34, 381/29, 364/485, 364/481, 364/487
• US Class Current: 704/205
• CPC Class Codes: G06F 17/14 Fourier, Walsh or analogous domain transformations , e.g. Laplace, Hilbert, Karhunen-Loeve, transforms for correlation function computation G06F17/156; spectrum analysers G01R23/16
• CPC Class Codes: G06G 7/26 Arbitrary function generators using Fourier series or other orthogonal functions G06G7/19; using curve followers G06K11/02
• CPC Class Codes: G06T 9/007 Transform coding, e.g. discrete cosine transform
• CPC Class Codes: H03B 5/20 with frequency-determining element comprising resistance and either capacitance or inductance, e.g. phase-shift oscillator
• CPC Class Codes: H03H 11/04 Frequency selective two-port networks
• CPC Class Codes: H03H 11/1252 Two integrator-loop-filters

Abstract

An analog circuit implementing a continuous wavelet transform forms a multiplicity of analog wavelet outputs. These analog wavelet outputs can be used for data compression. This analog circuit is estimated to be about one-hundredth (1/100) the size and power of a digital wavelet transform circuit. Additionally, the analog wavelet outputs of the analog wavelet transform chip is directly determined without the loss of information due to the digital sampling.

Claims

1. An analog circuit comprising:

modulating means for modulating a input signal with sinusoidal signals of different frequencies to form analog modulated signals, and

a bank of analog filters connected to receive said analog modulated signals from said modulating means, said bank of analog filters producing a multiplicity of analog wavelet outputs, said bank of analog filters comprising substantially half-Gaussian shaped filters.

2. The analog circuit of claim 1, wherein each filter of said bank of analog filters comprises a cascade of a number of follower-integrators.

3. The analog circuit of claim 1, wherein said modulating means comprises multipliers.

4. The analog circuit of claim 1 further comprising sinusoidal signal production means for producing said sinusoidal signals, said sinusoidal signal production means comprising divide-by-n circuits and low pass filters in a manner that the sinusoidal signals have frequencies that differ on a logarithmic scale.

5. The analog circuit of claim 4, wherein said sinusoidal signal production means further includes an oscillator.

6. The analog circuit of claim 4, wherein said sinusoidal signal production means further includes attenuate and bias circuitry.

7. The analog circuit of claim 4, wherein said sinusoidal signal production means includes phase shifting circuitry to produce two sinusoidal signals with each of the frequencies wherein one of the two sinusoidal signals is phase shifted from the other of the two sinusoidal signals.

8. The analog circuit of claim 1, further comprising circuitry for forming a reconstituted analog input signal from a multiplicity of analog signals.

9. The analog circuit of claim 8, wherein said reconstituted input signal forming circuitry comprises multipliers and summers.

10. The analog circuit of claim 9, further comprising a sinusoidal signal producing means for producing sinusoidal signals, wherein said multipliers receive said sinusoidal signals and said multiplicity of analog signals.

11. The analog circuit of claim 8, further comprising a sampler for sampling said analog wavelet outputs, an processor for encoding the sampled output and for decoding the sampled output to produce said multiplicity of analog signals.