Binary processing of sound spectrum

• US 4,634,966 A
• Filed: 03/19/1985
• Issued: 01/06/1987
• Est. Priority Date: 03/22/1984
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Nakamura, Shogo, Nakatani, Tomofumi
• Primary Examiner(s): Tokar, Michael J.
• Application Number:
  US06/713,431
• Time in Patent Office: 658 Days
• Field of Search: 324/77 R, 324/77 B, 324/77 C, 324/77 CS, 324/78 D, 324/79 D, 324/77 D, 328/140, 364/485, 364/487, 364/571, 375/10
• US Class Current: 324/76.24
• CPC Class Codes: G01H 3/08 Analysing frequencies present in complex vibrations, e.g. comparing harmonics present acoustic presence detection G01V1/001
• CPC Class Codes: G01R 23/16 Spectrum analysis; Fourier analysis

Abstract

A frequency spectral distribution of sound signal has a plurality of discrete data at respective channels where sampling takes place. Such a spectral distribution, defining a parallel signal, is converted into a time series signal which is used to produce a peak-detected signal and a zero-cross signal. Then, based on the timing of the zero-cross signal, the peak-detected signal is compared with the original parallel signal to process the original parallel signal to be binary-valued. The present invention provides a simple hardware structure having the above-described function.

Claims

1. A system of processing a spectrum of sound to be binary-valued, comprising:

sample and hold means for sampling and holding a parallel signal of said spectrum of sound;

converting means for converting said parallel signal into a time series signal;

peak detecting means for detecting a peak of said time series signal and for producing a peak-detected signal;

zero-cross detecting means for detecting zero-crossing of said time series signal and for producing a zero-cross signal;

comparing means for comparing the level of said parallel signal with the level of said peak-detected signal and for supplying a binary output signal as a result of a comparison using said peak-detected signal as a threshold;

means for supplying a control signal in association with said zero-cross signal; and

latching means for latching the binary output signal from said comparing means in accordance with said control signal.

2. The system of claim 1 wherein said peak-detected signal is weighted for use as a threshold.

3. The system of claim 1 wherein those portions of said parallel signal which reside in a time period while said zero-cross signal is at a selected one of the low and high level are latched at the same time by said zero-cross signal.