JPS6025100A - Waveform storage device - Google Patents

Abstract

PURPOSE:To permit a processing system to be flexible by employing processing elements such as a microprocessor to produce a small-sized constitution of a differential storage system waveform storage device, and allowing software, which controls the microprocessor, to perform the processing of the device. CONSTITUTION:When an interruption request occurs in a timer (a) for interruption generation, the microprocessor (b) reads comparison values alpha and beta between the holding data values of the previous values, which are generated through a ladder type resistance network (f) from 8-bit outputs gamma and delta of a general-purpose input/output element (e), and analogue signal values, which are impressed to an analogue signal input terminal (h). Next, alpha as well as beta are transferred to and stored in a memory (d) for storing differential data. The microprocessor (b) calculates the holding data to be outputted to gamma as well as delta, by using alpha and beta and the previous value holding data. This operation enables various methods, by changing the contents of a read-only memory (c) into different algorithm. The calculated holding data are retained by the general purpose input/output element (e). This processing is executed for each interruption request of the timer (a).

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a relatively small-scale configurable waveform storage device that stores differential binary data in a storage circuit using a differential storage method and reproduces the data. It is.

(Background Art) A waveform storage device that encodes the waveform of an analog signal and stores it in a storage circuit has generally been composed of an analog-to-digital converter, a data processing transfer circuit, a storage circuit, a digital-to-analog conversion circuit, etc. . Furthermore, even in waveform storage devices configured using the delta modulation method, the processing method has generally been fixed by creating a dedicated circuit. Therefore, in order to change the processing method of the device, it is necessary to change the dedicated circuit, and the flexibility of the device is poor. Another disadvantage is that a large number of elements are required for the configuration, except when the dedicated circuit described above is integrated into an integrated circuit.

(Problems to be solved by the invention) In order to solve these drawbacks, it is an object of the present invention to configure a small-scale waveform storage device using a differential storage method by using arithmetic processing elements such as microprocessors, and to By having the processing method performed by software that controls a microprocessor, it is possible to provide flexibility in the processing method of the device.

The device of the present invention has the following nine features.

The processing method for tOV memory is the responsibility of the software that controls the MicroProsensor.

(2+ Since the processing method for M-type memory is handled by software, it is easy to change the processing method, and the system is flexible.

(3) It does not have peripheral circuits such as analog-to-digital conversion circuits that process input analog signals, and the overall circuit configuration is small.

(4) The analog-to-digital conversion operation of input analog signals is included in a feedbank system consisting of a microprocessor and software that controls it.

(5) Since the differential data storage and arithmetic processing for the input analog signal are performed by the microprocessor, the input analog signal period is defined by the processing speed of the microprocessor itself.

(Structure and operation of the invention) FIGS. 1 and 2 show embodiments of the present invention, with FIG. 1 being a simple block diagram and FIG. 2 being a detailed block diagram.

a is an interrupt generation timer for giving periodic interrupts to the microprocessor; b is a microprocessor for arithmetic processing and data transfer to memory; 1C is a read-only memory IJ-1d for storing waveform-based algorithms;
kX memory for storing differential data, e is a general-purpose input/output element for holding previous value data and inputting differential data, f is a ladder-type resistor network for converting an 8-bit digital value into an analog value, and g is an input analog signal. This is a comparator that compares data held at previous values. h is an analog signal input terminal for applying an analog waveform to be stored, and 1 is an analog signal output terminal for reproducing and outputting the stored analog waveform. J is an address bus supplied by the microprocessor, and k is a data bus for exchanging data with the microprocessor.

The operation of this device will be explained below. This embodiment has a circuit configuration with two comparators.

In Fig. 2, a is an interrupt generation timer for periodically giving an interrupt to the microprocessor sensor for calculation and data transfer in b, and is used to process differential data for input analog signals and to memory for storing differential data. The transfer layer and the interrupt processing program of the microprocessor are processed together.

When an interrupt request occurs in the interrupt generation timer of a,
The microprocessor of b is the general-purpose input/output element of e.
The previous held data values generated from the bit outputs γ and δ through the ladder-type resistor network of f, i.e., the values at points B and D of the comparator of g, and the analog signal applied to the 11 analog signal input terminals. The signal values, ie, the comparison values of g with point A and 0 of the comparator, ie, α and β, are read through the data bus of k.

Next, the read difference data 2 bits α and β are
The difference data α and β are stored by being transferred to the difference data storage angle memory d through the data bus k.

Next, using the difference data α and β and the previous value retention data, b
The microprocessor then calculates the held data to be output to γ and δ. This calculation normally uses a delta modulation algorithm, but since the algorithm is stored in the read-only memory of C,
By changing the contents of the read-only memory to a different algorithm, various methods such as single type delta modulation and double integral type delta modulation are possible.

The retained data calculated by the microprocessor of b is
It is held by the general-purpose input/output element of e. At the time of the next interrupt request by a -9 The above held data and the analog input signal from the analog signal input terminal at that point are compared by the comparator g, and the next difference data is generated at α and β. be done. The basic operation of this device is to store differential data in the differential data storage memory d by executing this process for each timer interrupt request a, and the system as a whole forms a feedback system.

In order to reproduce the differential take accumulated in the differential data storage memory of d, the microprocessor of b operates according to the arithmetic algorithm stored in the read-only memory of C, and the result of the operation is sent every timer interrupt of a. This can be achieved by outputting to δ of the general-purpose input/output element of e.

FIG. 3 is a graph for explaining the operation of the embodiment, and in both (1) and (2), the horizontal axis represents the time axis, and the vertical axis represents the amplitude. a is the analog signal waveform input to the comparator, b is the previous value taken value at each sample time, and C is the value of a-b, that is, the difference data.

Various methods can be considered for the differential take generation mechanism of the waveform storage device, but in the case of a single delta modulation method, there are 1
To determine the differential take cC, ]] at the first sample time, the input signal values a (n) and 1]- at time n are determined.
The previous data value at time 1, b(n-1), is used. In the case of the double integral delta modulation method, ac! is used to determine C(6). ]], b Cn, -1), fi-2
The previous data value at the time, ie, b(n, -2), is used to determine the method. To determine the difference data C(6),
I] The more data from n-2, 11-3, the previous sample, and the sample before the previous sample other than time point -1 are used, the more the input waveform
Although it is possible to memorize a similar waveform and reduce grannyler noise in the waveform, it takes a lot of time to calculate the previous value data c[n], and the frequency band of the input analog signal to be used is limited. Become.

As explained above, this waveform storage device functions as a device with a relatively small-scale circuit configuration, and since the processing method of waveform storage is handled by software, the processing method can be easily changed and the system is flexible. There are advantages such as:

Also, in this embodiment, there are two sets of differential data input circuit, previous value take holding circuit, and comparator, but by having two sets of the above three elements, the comparison level for the input analog signal becomes two levels. Since the comparison level in the case of a set of the above three elements improves the followability of the waveform to the input signal compared to the level, it becomes possible to reduce granular noise in the follow-up region. - When there are n sets of the above three elements in the set, the difference data generated by one interrupt process will be n bits, so as the value of n increases, the followability to the input signal improves and granular noise can be expected to be reduced, but the memory for storing differential takes will increase, and
Since the arithmetic processing time becomes longer and the input chi-g frequency decreases, it is desirable that the value of n be determined as necessary. Generally speaking, it can be said that n=2 to 3 is good in a low frequency region for purposes such as speech synthesis.

(Effects of the Invention) The present invention functions as a device with a relatively small-scale circuit configuration, and since the waveform storage processing method is handled by software, the processing method can be easily changed and the system is flexible. .

Currently, the average execution time for one instruction of a general-purpose microprocessor is 1 to 5 microseconds, so it is possible to sample one cycle of the input Bunalog signal to be stored 10 to 100 times. It can be used effectively in various fields.

[Brief explanation of drawings]

1 and 2 are block diagrams of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of the operation. Explanation of symbols; Figures 1 and 2 a... Timer for interrupt generation b... Microprocessor - C... Read-only memory for storing processing algorithms d... Memo for storing differential data +7- e. ... General-purpose input/output element f for holding previous value data and inputting differential take... Ladder type resistance network g ... Comparator 1] ... Terminal B for signal input ... Terminal J for signal output ... etc. Microbro sensor address output line k.
... Explanation of the line code for data output of the microprocessor; Fig. 3 a ... Input signal waveform b ... Previous value holding data value C ... Difference' data a (, ]) is the number 111. Kugata signal value 1 at sample time
) [r+) is the previous value held data value at the 11th sample b(n-]) is the previous value held data value at the 11111th sample C[11] is the difference data at the nth sample Value patent applicant: Oki Electric Industry Co., Ltd. Patent application agent: Megumi Yamamoto −

Claims (1)

[Claims] In a waveform storage device that stores difference data generated from an input signal and previous value data in a storage circuit, and reproduces the original input signal by synthesizing the stored difference data, the input signal and previous value data are A comparator for comparison, a ladder resistor network for converting digital values into analog values, a memory circuit for storing the difference data output from the comparator, and a microcontroller for transferring the difference data to the memory circuit and performing arithmetic processing. A processor, an interrupt generation timer for giving periodic interrupts to the microprocessor, a general-purpose input/output element for holding previous value data and inputting differential data, and a memory for storing processing algorithms of the microprocessor. A waveform storage device characterized by: