JPH08335849A - Integrated circuit, variable filter adjustment method for the circuit, and electronic equipment using the circuit - Google Patents

Abstract

PURPOSE: To automatically correct the variance in input/output response characteristic of an external element in accordance with the adjustment of the variance in input/output response characteristic and the temperature characteristic of an internal element of an integrated circuit. CONSTITUTION: A control signal applied to first variable filters 35 and 36 is adjusted externally or internally, and the adjusted control signal is subjected to digital/analog conversion by a D/A converter 33 as the reference. A second variable filter 34 is corrected based on the converted control signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated circuit,
In particular, the present invention relates to an integrated circuit capable of adjusting the characteristics of a variable filter, a method for adjusting a variable filter of the integrated circuit, and an electronic device using the integrated circuit.

[0002]

2. Description of the Related Art Recently, an integrated circuit used in an image recording / reproducing apparatus such as a VTR has a built-in variable filter and corrects variations and temperature characteristics of elements (resistors, capacitors, transistors, etc.) in the integrated circuit. To do this inside the integrated circuit
Or it tends to be configured to adjust the variable filter externally.

Conventionally, as a method of adjusting this kind of filter, a circuit as shown in FIG. 8 or 9 is known.

FIG. 8 and FIG. 9 are circuit block diagrams of a main part of an integrated circuit of this type.

A control circuit including the integrated circuit shown in FIG. 8 has a constant current source 81 inside the integrated circuit 80 and an external volume 84.
The variable filters 82 and 83 in the integrated circuit 80 are adjusted at the same time by adjusting the constant current source 81 and using it as a bias of the variable filters 82 and 83.

Also in the case of automatically adjusting inside the integrated circuit 80, as shown in FIG. 9, the reference signal and the signal after passing through the reference variable filter 87 are phase-compared by the phase comparator 88, The error is automatically adjusted by returning to the reference variable filter 87, and this control signal is used for the variable filter in the integrated circuit 80 to simultaneously adjust the variable filters 82 and 83.

[0007]

However, in order to adjust the variation and temperature characteristics of the elements (resistors, capacitors, transistors, etc.) in the integrated circuit 80, the variable filters 82, 83 in the integrated circuit are adjusted at the same time. It is a thing.

Therefore, as shown in FIGS. 8 and 9, a variable filter for correcting the variation of externally attached elements, for example, a variable delay line equalizer 85 for correcting the delay amount of the 1H delay line 86 is an integrated circuit. It couldn't be built into the 80, but it was external. For this reason,
There are problems such as an increase in external parts and an increase in board area.

Further, the external variable filter is usually adjusted by a volume, and it is difficult to cope with automation of adjustment.

The present invention has been made to solve the above problems, and a control signal input to a first adjusting unit for adjusting variations in elements and temperature characteristics in an integrated circuit is supplied to a reference of a digital / analog converter. As digital /
By inputting to the second adjusting unit that performs analog conversion and adjusts the external element, it is possible to follow the variation of the internal element and the adjustment of the temperature characteristic and automatically correct the variation of the external element. Provided are an integrated circuit having a small size, a method of adjusting a variable filter of the integrated circuit, and an electronic device using the integrated circuit.

[0011]

The present invention has been made to solve the above problems, and it is a first aspect of the present invention to adjust the variation in input / output response characteristics or the temperature characteristics of each element integrated in a circuit. Adjusting means, second adjusting means for adjusting variations in input / output response characteristics of each element externally attached to the circuit, and a control signal adjusted by the first adjusting means for reference of a digital / analog converter. And a correction means for performing digital / analog conversion to correct the adjustment amount of the second adjustment means.

[0012] Further, the first is for adjusting variations in input / output response characteristics or temperature characteristics of each element integrated in the circuit.
And an adjusting means, a first variable filter adjusted by the first adjusting means, and a second variable filter adjusting an input / output response characteristic variation of each element externally attached to the circuit. In the circuit variable filter adjustment method, a control signal applied to the first variable filter is digital-to-analog converted as a reference of a digital / analog converter, and a second variable filter is generated based on the converted control signal. The feature is that it is corrected.

An integrated circuit used in an electronic device for inputting an image signal, converting the signal, and recording the signal on a recording medium, the constant current means outputting an adjusted current based on the adjustment signal, and an external circuit Receiving the adjustment data supplied from the constant current source, a constant current output from the constant current source, and a generating unit for generating a control signal based on the adjustment data received by the receiving unit; And an adjusting means for adjusting an image signal supplied from the outside based on the generated control signal.

Further, in an electronic device for inputting an image signal, converting the signal and recording it on a recording medium, a constant current means for outputting an adjusted current based on the adjustment signal, and an adjustment for generating adjustment data. A data generating unit, a receiving unit that receives the adjustment data, a constant current output from the constant current source, and a generating unit that generates a control signal based on the adjustment data received by the receiving unit; A delay unit that produces an image signal delayed by one horizontal scanning period from the above, and an adjusting unit that adjusts the image signal produced by the delay unit based on the control signal produced by the producing unit.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) An embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an image recording apparatus to which the present invention is applied.

In the figure, reference numeral 1 is a camera unit, which is composed of a lens 11, a CCD 12, and a signal processing unit 13. The camera unit 1 captures an image, converts it into an image signal, and outputs it. Reference numeral 2 is a recorder unit, which is composed of a recording signal processing unit 21, a reproduction signal processing unit 22, and a head amplifier unit 23.
The recorder unit 2 stores an image signal output from the camera unit 1 or an image output device (not shown) in a recording medium via the magnetic head 3 and displays it on the monitor unit 4, or
The monitor unit 4 reproduces the image signal read from the recording medium.
To be displayed.

The recording signal processing unit 21 converts the input image signal into a signal for recording on a recording medium via the magnetic head 3.

The reproduction signal processing section 22 converts the signal read from the recording medium via the magnetic head 3 into a signal for displaying on the monitor section 4.

FIG. 2 is a block diagram showing essential parts of the recording signal processing section 21 and the reproduction signal processing section 22.

In this embodiment, the processing unit including the recording signal processing unit 21 and the reproduction signal processing unit 22 is composed of a one-chip IC.

In the figure, a video signal is input to the YC separation unit 30 from the camera unit 1 or an external input, and is separated into a luminance signal (Y signal) and a carrier color signal (C signal), which are divided into AGC 211 and ACC 215, respectively. Is output. Also Y
A 1H delay unit 40 is connected to the C separation unit 30.
A 1H delay unit 40 is connected to the YC separation unit 30.

The AGC 211, LPF 212, emphasis 213, and FM modulator 214 constitute a Y signal recording system.

The AGC 211 outputs the input signal to the FM.
The modulation unit 214 is adjusted so as to have an optimum input level.

The LPF 212 prevents the sound carrier wave and the high frequency component noise contained in the input signal from being mixed in the Y signal.

The emphasis 213 enhances the high frequency band of the input signal.

The FM modulator 214 performs FM modulation on the input signal.

The ACC 215, the emphasis 216, the frequency converter 217 and the LPF 218 constitute a C signal recording system.

The ACC 215 sets the level so that the output signal level becomes constant even if the input signal level fluctuates.

The emphasis 216 enhances the input signal.

The frequency converter 217 converts the frequency of the input signal.

The LPF 218 removes high frequency components of the frequency-converted input signal.

In this way, the video signal can be recorded by sending the signals output from the Y signal recording system and the C signal recording system to the head amplifier 23.

When reproducing the signal recorded on the medium,
The reproduced signal output from the head amplifier 23 is H
The converted carrier color signal is cut by the PF 224 to extract only the luminance signal having a predetermined frequency or higher.

The FM demodulator 223 converts the input signal to F
M demodulate.

The LPF 222 removes visual noise from the input signal.

The de-emphasis 221 is the emphasis 2
The part amplified in 13 is returned to the original level.

The LPF 228 also removes high frequency components from the input signal, and then the frequency converter 227.
Returns to the frequency before being converted by the frequency converter 217.

The BPF 226 extracts a signal having a frequency within a predetermined range from the input signal.

The de-emphasis 225 restores the signal amplified by the above-mentioned emphasis 216 to the original level.

Then, by sending the signals obtained by synthesizing the respective signals to the monitor unit 4, the reproduced video can be viewed.

FIG. 4 is a diagram showing the waveforms and frequency distributions of the signals of the respective parts in FIG. 2, (a), (b) ...
(H) shows the waveform and frequency distribution in (a), (b) ... (h) in the figure, respectively. It should be noted that the frequencies shown in the figure are examples and may differ depending on various methods.

FIG. 3 is a detailed block diagram of a portion of the YC separation unit 30 relating to the present invention.

In the figure, 31 is a constant current source, which is adjusted by an external volume 50. The adjusted constant current is mirrored, and the variable filters 35 and 3 are used as control signals.
6 is input as a bias signal, and the D / A converter 3
Input to 3. The D / A converter 33 is, for example, as shown in FIG.
, 33c, and controls the switches 33a, ..., 33c corresponding to the digital data output from the serial / parallel conversion unit 32, and the current I from the constant current source 31 is switched to the switches 33a ,. , 33c are variably controlled and output as an output. The data input to the D / A converter 33 is as shown in FIG.
The parallel data (D1, D2, ...) Converted by the serial / parallel converter 32 from the adjustment data (DATA) output from the control microcomputer (not shown).

The output of the D / A converter 33 is input to the variable filter 34 (eg, variable delay equalizer) as a bias. The variable filter 34 receives the signal from the external 1H delay unit 40, delays the signal by a fixed amount, and outputs the delayed signal. FIG. 5B shows the relationship between the input / output signal of the 1H delay unit 40 and the input / output signal of the variable filter 34.

In the above structure, the external volume 5
0 is adjusted so as to correct variations in cutoff frequencies and Q values of the variable filters 35 and 36 due to variations in input / output response characteristics of internal elements (resistors, capacitors, transistors, etc.).

The variable filters 35 and 36 are, for example,
A Y signal band limiting filter included in the LPF 212,
Low frequency chroma (NTSC: 743 KHz, PAL: 732 KHz) after frequency conversion of C signal included in LPF218
Etc.) extraction filter, a filter for reproducing DC after FM demodulation of the Y signal included in the LPF 222, BP
After frequency conversion of C signal of F226 fsc ± 500 KHz
It is a filter for extracting the chroma band of.

At the same time, the adjusted constant current is D / A
Input as the reference current of the converter 33, D
Since it is also input to the variable filter 34 via the / A converter 33, variations in the delay amount of the variable filter (variable delay equalizer) 34 due to variations in internal elements (resistors, capacitors, transistors, etc.) are also corrected.

Further, regarding the variable filter 34, D
By controlling the digital data input to the A / A converter 33, the variation in the delay amount due to the variation in the internal elements (resistors, capacitors, transistors, etc.) is corrected, and the variation in the external 1H delay unit 40 is corrected. It can also be corrected.

In this embodiment, the YC separation unit 1
Although the serial / parallel converter 32 is built in the chip, parallel data may be directly input from the outside.

Further, the case where the adjustment is performed so as to correct the variation of each internal element has been described, but the same configuration can be applied to the case where the cutoff frequency or Q value of the variable filter is switched by mode switching or the like.

As described above, according to the present embodiment, the external communication means (serial / parallel converter 32) for setting the correction amount corrected by the variable filter 34 is provided, and the correction corrected by the variable filter 34 is provided. The amount can be set based on an external input and the setting of the correction amount can be automated.

(Second Embodiment) FIG. 7 shows a second embodiment of the present invention.
Is a block diagram of a main part of an integrated circuit showing an embodiment of
The same components as those in FIG. 3 are denoted by the same reference numerals.

In the figure, an integrated circuit (YC separation section) 30
A variable filter 71 and a phase comparator 72, which serve as a reference, are provided in the.

A reference signal having a predetermined frequency is input to the reference variable filter 71 from a reference signal source (not shown). The output of the reference variable filter 71 is input to the phase comparator 72. The phase comparator 72 is a reference variable filter 71.
The error signal obtained by comparing the phases of the output signal and the reference signal is converted into a current signal for controlling the reference variable filter 71 and fed back to the reference variable filter 71.

With this loop, the phase difference between the input signals of the phase comparator 72 is automatically controlled so as to have a predetermined value, that is, the cutoff frequency of the reference variable filter has a predetermined value.

The bias current of the reference variable filter 71, which is automatically controlled by the above loop, is mirrored and input to the variable filters 35 and 36 as a bias, and D /
It is input as a reference of the A converter 33.

After that, the operations of the D / A converter 33, the variable filter 34, and the 1H delay section 40 are the same as those in the first embodiment.

In the integrated circuit 30 thus configured, the automatic adjustment loop processing section 70 includes internal elements (resistors,
The reference variable filter 71 and the variable filters 35 and 36 are automatically adjusted to correct variations in the cutoff frequencies and Q values and temperature characteristics due to variations in capacitors and transistors) and temperature characteristics.

At the same time, the constant current, which is the controlled bias, controls the digital data (adjustment data) input to the D / A converter 33, so that variations in internal elements (resistors, capacitors, transistors, etc.) and Variable filter (variable delay equalizer) based on temperature characteristics 3
The variation of 4 and the temperature characteristic are also corrected.

Further, regarding the variable filter 34, D
By controlling digital data (adjustment data) input to the / A converter 33, variations in internal elements (resistors, capacitors, transistors, etc.), variations in delay amount due to temperature characteristics, and temperature characteristics are corrected,
The 1H delay unit 40 can be adjusted to correct the variation.

[0062]

As described above, according to the present invention, the correction means performs the digital / analog conversion of the control signal adjusted by the first adjusting means as the reference of the digital / analog converter, and the second adjusting means. Since the correction amount of the external element is corrected, the correction means for correcting the variation of the input / output response characteristics of the external element can be incorporated in the circuit board, and the external element variation correction can be followed by the output from the first adjusting means. You can do it.

Further, since the correction amount of the second adjusting device derived from the correction device is set via the external communication device, the setting of the correction amount can be easily automated.

Further, the control signal applied to the first variable filter is adjusted externally or internally, and the adjusted control signal is digital-to-analog converted as a reference of a digital / analog conversion value, and the converted signal is converted. Since the second variable filter is corrected based on the control signal, variations in the input / output response characteristics of each element integrated inside the circuit or variations in the input / output response characteristics of the external elements follow the adjustment of the temperature characteristics. Can be corrected.

Further, since the correction amount for correcting the second variable filter is set based on the converted control signal via the communication port, the setting of the correction amount can be easily automated.

Therefore, the substrate area can be reduced, and
It is possible to automatically correct the variation in the input / output response characteristic of the external element by following the variation in the input / output response characteristic of the integrated circuit internal element and the adjustment of the temperature characteristic.

[Brief description of drawings]

FIG. 1 is a block diagram of an image recording apparatus to which the present invention has been applied.

FIG. 2 is a block diagram showing main parts of a recording signal processing unit 21 and a reproduction signal processing unit 22.

FIG. 3 is a detailed block diagram of a portion of the YC separation unit 30 relating to the present invention.

FIG. 4 is a diagram showing waveforms and frequency distributions of signals at various parts in FIG.

FIG. 5 is a diagram showing a relation of signals of respective parts in FIG.

FIG. 6 is a configuration diagram showing an example of a D / A converter 33.

FIG. 7 is a block diagram of a main part of an integrated circuit showing a second embodiment of the present invention.

FIG. 8 is a block diagram illustrating a main part of a conventional integrated circuit.

FIG. 9 is a block diagram illustrating a main part of a conventional integrated circuit.

[Explanation of symbols]

 1 camera section 2 recorder section 3 magnetic head 4 monitor section 11 lens 12 CCD 13 signal processing section 21 recording signal processing section 22 reproduction signal processing section 23 head amplifier section 30 YC separation section 31 constant current source 32 serial / parallel conversion section 33 D / A converter 34 variable filter 35, 36 variable filter 40 1H delay unit 71 reference variable filter 72 phase comparator 211 AGC 212, 218, 222, 228 LPF 213, 216 emphasis 214 FM modulator 215 ACC 217, 227 frequency converter 221 225 De-emphasis 223 FM demodulator 224 HPF 226 BPF

Front page continued (72) Inventor Nobuyuki Hirayama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (13)

[Claims] 1. A first adjusting means for adjusting a variation in input / output response characteristics or a temperature characteristic of each element integrated in a circuit, and a variation in input / output response characteristic of each element externally attached to the circuit. And a control signal adjusted by the first adjustment means as a digital / analog converter reference.
An integrated circuit, comprising: a correction unit that performs analog conversion to correct the adjustment amount of the second adjustment unit. 2. The integrated circuit according to claim 1, further comprising external communication means for setting a correction amount of the second adjusting means corrected by the correcting means. 3. A first adjusting means for adjusting variations in input / output response characteristics or temperature characteristics of each element integrated in the circuit, and a first variable filter adjusted by the first adjusting means. A variable filter adjusting method for an integrated circuit, comprising: a second variable filter that adjusts variations in input / output response characteristics of each element externally attached to the circuit, wherein a control signal applied to the first variable filter is digital. Digital-to-analog conversion as a reference of the analog / analog converter, and a second signal based on the converted control signal.
A method for adjusting a variable filter of an integrated circuit, characterized in that the variable filter of (1) is corrected. 4. The variable filter adjusting method according to claim 3, wherein a correction amount for correcting the second variable filter is set via a communication port based on the converted control signal. 5. An image signal is input, the signal is converted,
An integrated circuit used in an electronic device for recording on a recording medium, comprising: a constant current means for outputting an adjusted current based on an adjustment signal, a receiving section for receiving adjustment data supplied from the outside, and a constant current source A generator that generates a control signal based on the output constant current and the adjustment data received by the receiver, and an adjustment that adjusts an image signal supplied from the outside based on the control signal generated by the generator. And an integrated circuit. 6. The integrated circuit according to claim 5, wherein the image signal is an image signal delayed by one horizontal scanning period. 7. The integrated circuit according to claim 5, wherein the adjusting means matches the horizontal synchronization of the image signal. 8. The integrated circuit according to claim 5, wherein the adjusting means is a variable delay equalizer. 9. The integrated circuit according to claim 5, wherein the integrated circuit comprises an IC of one chip. 10. An electronic device for inputting an image signal, converting the signal, and recording the recording signal on a recording medium, a constant current means for outputting an adjusted current based on the adjustment signal, and an adjustment for generating adjustment data. A data generating unit, a receiving unit that receives the adjustment data, a constant current output from the constant current source, and a generating unit that generates a control signal based on the adjustment data received by the receiving unit; And a delay unit that generates an image signal that is delayed by one horizontal scanning period, and an adjustment unit that adjusts the image signal generated by the delay unit based on the control signal generated by the generation unit. Electronics. 11. The electronic device according to claim 10, wherein the adjusting unit adjusts horizontal synchronization of the image signal. 12. The electronic device according to claim 10, wherein the adjusting unit is a variable delay equalizer. 13. The electronic device according to claim 10, wherein the constant current unit, the receiving unit, the generating unit, and the adjusting unit are constituted by a one-chip IC.