JPS58131864A - Waveform storage generating circuit - Google Patents

Abstract

PURPOSE:To use storage information to eliminate distorted signal components from a real signal, by storing a signal for distortion compensation to a rewritable non-volatile memory after converting the signal into a digital signal, and picking up the storage information after converting into an analog signal as required. CONSTITUTION:Waveform data to an input terminal 3 of a waveform storage generating circuit are formed by converting a waveform signal at an AD converter (not shown) and the waveform data are transferred to the non-volatile memory 1 or a DA converter 5 at a switching circuit 4. Thus, the memory 1 stores the waveform data via the switching circuit 4 semi-permanently, the data is given to the DA converter 5 through the circuit 4 with a control signal to a control terminal 2, and a prescribed waveform analog signal is generated from the DA converter 5. This waveform storage generating circuit is used, for instance, for a signal circuit for distortion compensation of a video camera.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is capable of storing an arbitrary signal waveform and generating this signal waveform when necessary.
Furthermore, the present invention relates to a waveform storage generation circuit that can also be provided with a function of changing a stored signal waveform to a different signal waveform.

Converted signals obtained from elements (devices) with nonlinear characteristics such as various sensors often contain distortion due to these characteristics, and in devices where this distortion is a problem, it is necessary to correct the distortion. It is necessary to generate a correction waveform for this purpose.

For example, a video camera achieves its purpose by photographing a subject using an image pickup tube and reproducing a faithful image of the subject. However, the actual signal obtained by imaging the subject usually contains distortion,
In order to obtain a faithfully reproduced image, it is necessary to combine a distortion correction signal and a signal containing distortion, and to cancel out the distortion signal component in the actual signal with the distortion correction signal. For this reason, it has been necessary for video cameras to incorporate this distortion correction signal inside the camera.

In addition, since the distortion contained in the actual signal differs depending on the characteristics of the image pickup tube, which is the main component of the video camera, the distortion correction signal must be different for each video camera. In reality, when manufacturing a video camera, it is necessary to incorporate a distortion correction signal suitable for each video camera by adjusting variable elements such as variable resistors in the circuit that generates the distortion correction signal. .

Such adjustment requires adjustment work by a skilled person, and there are problems in that not only does it take a long time, but it is still insufficient to incorporate a complete distortion correction signal.

In this way, it is extremely difficult to create a predetermined signal waveform by making full use of analog circuit technology, and the formation of signal waveforms must be done using hardware technology, and in particular, it is difficult to deal with changes in signal waveforms. It was extremely difficult to get rid of it.

The present invention provides a waveform memory generation circuit that can eliminate such conventional problems, and provides a digital signal for distortion correction in a rewritable nonvolatile memory or a nonvolatile memory such as a mask ROM. The feature is that this stored information can be converted into an analog signal and retrieved when necessary.

The waveform memory generation circuit of the present invention will be explained below with reference to the drawings.

The figure is a block diagram showing an example of the configuration of a waveform storage generation circuit according to the present invention, in which 1 is a rewritable non-volatile memory for storing information of a predetermined waveform, and 2 is a non-volatile memory 1.
3 is an input terminal to which waveform data is input; 4 is a control terminal for decoding the contents of input terminal 3;
5 is a DA converter, and 6 is a waveform output terminal).

The waveform data inputted to the input terminal 3 of the waveform storage generation circuit of the present invention configured as described above is converted and formed by a waveform signal AD converter (not shown), and this waveform data is converted into a non-volatile state by the switching circuit 4. Memory 1 is also transferred to DA converter 6.

That is, the nonvolatile memory 1 semipermanently stores the waveform data transferred via the switching circuit 4. Note that the switching circuit 4 functions not only to switch the transfer path of waveform data from the input terminal 3 but also to transfer the waveform data 'f stored in the nonvolatile memory 1 to the DA converter 5.

By the way, in the waveform storage generation circuit of the present invention shown in the above embodiment, a predetermined waveform is stored as digital data in a nonvolatile memory that can permanently store information numbers as described above, and this digital data is stored. A control signal to the control terminal 2 is sequentially sent through the switching circuit 4 to the DA converter 5, and the DA converter 5 converts it into an analog value, thereby generating a predetermined waveform at the output terminal 6. Explode. In addition, since the waveform data stored in the non-volatile memory 1 can be rewritten as necessary, it is effective when it is necessary to change the waveform data and change the generated waveform over time. It is.

In the embodiment, a rewritable nonvolatile memory is shown, but a mask ROM may also be used instead. In this case, although the storage of the waveform data is permanent, it is impossible to rewrite the data once stored, so it is not possible to change the waveform data as in the case of using rewritable non-volatile memory. I can't. Furthermore, when storing waveform data, a predetermined waveform may be converted into a digital code, and the waveform data may be stored (written) based on this digital code (using a mask pattern).

When the waveform storage generation circuit of the present invention described above is used, for example, as a signal circuit for distortion correction in a video camera (11-j), it is preferable to output the stored waveform from the output terminal in synchronization with the video signal.

Furthermore, when the distortion correction is not enough to correct one type of waveform, it is difficult to prepare a necessary number of waveform storage generation circuits and individually store the necessary waveform data.

If a waveform is output based on the data stored from the controller, a wide variety of correction functions can be performed.

As is clear from the above explanation, the waveform storage generation circuit of the present invention differs from conventional waveform generation methods using analog circuit technology in that it is capable of generating a predetermined waveform based on stored data. There is no need to provide any adjustment function to the waveform storage generation circuit itself.

Incidentally, since it is sufficient to prepare a dedicated waveform generator for the waveform data in the form 11j3jid and use this, there is no need to add adjustment work to each waveform generator circuit as in the past. Adjustment work can also be simplified.

Note that the use of the waveform storage generation circuit of the present invention is limited to a signal generation circuit for distortion correction.

[Brief explanation of drawings]

The figure is a block diagram showing an example of the configuration of a waveform storage generation circuit according to the present invention. 1...Non-volatile memory, 2...Control terminal, 3...Waveform data input terminal, 4...-
...Switching circuit, 5...DA converter, 6.
...Waveform signal output terminal.

Claims (4)

[Claims] (1) A nonvolatile storage device that stores analog waveforms as digital data, and a DA converter that converts the digital data stored in the nonvolatile storage device into analog signals, and is capable of storing and generating the analog waveforms. A waveform memory generation circuit characterized by: (2) The waveform memory generation circuit according to claim 1, wherein the nonvolatile memory device is a rewritable nonvolatile memory device. (3) The waveform memory generation circuit according to claim 1, wherein the nonvolatile memory device is a mask ROM. (4) An analog waveform signal for correcting distortion signal components contained in an analog waveform signal obtained by imaging with an imaging device of a video camera is stored as digital data, and the digital data is output in synchronization with the video signal. ,--A non-volatile storage device and a DA converter that converts digital data output from the non-volatile storage device into an analog signal; A waveform memory generation circuit characterized in that it generates an analog waveform signal.