Miscellaneous active electrical nonlinear devices – circuits – and – Specific identifiable device – circuit – or system – Unwanted signal suppression
Reexamination Certificate
2000-02-24
2001-10-16
Le, Dinh T. (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Specific identifiable device, circuit, or system
Unwanted signal suppression
C708S321000, C708S312000, C327S551000
Reexamination Certificate
active
06304133
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an average calculating circuit which calculates and outputs the average of an input signal, in particular to a moving average filter for calculating the moving average of the input signal.
2. Description of Related Art
The moving averaging method is a method for smoothing a signal (For example, Reference I: “Beginner's Digital Filter” Nov. 30, 1989 pp. 9-15 by Shougo Nakamura, Tokyo Denki University Press). According to this moving averaging method, the moving average is calculated as follows. When the k-th moving average is available and the (k+1)-th moving average needs to be calculated, the difference between the oldest data of all the data used in obtaining the k-th moving average and the new data that is input to obtain the (k+1)-th moving average is added to the k-th moving average to obtain the (k+1)-th moving average (p14 in Reference I). The advantage of this method is that the amount of computation in obtaining the moving average is reduced. However, since the difference between the oldest data and the new data is added to the moving average already obtained to obtain the next moving average, once a calculation error occurs by a noise or an operation error, the calculation error propagates indefinitely, which is a problem.
Moreover, occasionally in the prior art, moving averages are first obtained in multiple stages and the moving average of the multiple moving averages is taken. When the number of stages of the moving averages is large, the amount of hardware has to be increased to a great extent in accordance with the number of the moving averages, which is another problem.
SUMMARY OF THE INVENTION
Given these problems, it is an object of the present invention to provide a moving average filter capable of solving these problems.
To solve the above-stated problems, a representative moving average filter according to the present invention has a data holding unit for holding multiple successive data, a coefficient storing unit for storing coefficients, a first adder which calculates the sum of a pair of data of a prescribed combination held in the data holding unit, a multiplier which multiplies the sum by coefficient data obtained from the coefficient storing unit, and a second adder which adds up a prescribed number of multiplication results produced by the multiplier.
REFERENCES:
patent: 5079734 (1992-01-01), Riley
patent: 5301134 (1994-04-01), Maruyama
patent: 9-238048 (1997-09-01), None
Le Dinh T.
OKI Electric Industry Co., Ltd.
Rabin & Berdo P.C.
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