JPH02302196A - Hue controller - Google Patents

Abstract

PURPOSE:To allow the use of a device which has not conversion processes of a carrier chrominance signal and a color difference signal by modulating the demodulated color difference signal to the carrier chrominance signal and switching the modulated carrier signal to a fixed phase carrier signal and a variable phase carrier signal. CONSTITUTION:The carrier chrominance signal inputted to an input terminal 1 is demodulated by a demodulator 7 with the output signal of an oscillator 6 and the signal, which is phase shifted by 90 deg. in a 90 deg. phase shifter 8, as carrier signals, and demodulated signals are supplied to a modulator 50. The modulator 50 modulates these signals with the output signal of an SW circuit 51 and the 90 deg. phase shifted signal as carrier signals and outputs the modulated signal to an output terminal 52. Thus, the signal outputted to the output terminal 52 is equal to the carrier chrominance signal inputted to the input terminal 1. With respect to the carrier chrominance signal, the hue is expressed with the chroma signal phase to the burst signal phase. Consequently, the chrominance signal which is outputted to the output terminal 52 is the carrier chrominance signal which is hue controlled by a control terminal 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hue control device used in a VTR or the like.

[Conventional technology]

FIG. 4 is a block diagram showing a hue control device used in a color TV receiver.

In the figure, l is an input terminal into which a carrier color signal is input, and 2
is a control terminal for controlling the phase controller 5; 3 is an input terminal to which a burst gate pulse is input; 4 is a burst canceling circuit for canceling the burst signal in the carrier color signal; and 5 is a signal phase shifter using the control terminal 2. 6 is an oscillator that generates a signal of approximately 3.58 MHz synchronized with the burst signal frequency in the carrier color signal inputted to input terminal 1;
7 is the carrier color signal input to input terminal 1 at approximately 3°58M.
Demodulator that demodulates the signal of t(z), 8 is the signal phase of 90
90° phase shifter for shifting the phase; 9 is a matrix driver circuit that converts the output signal of the demodulator 7 into three primary color signals of R, G, and B; 10 is an input to which a luminance signal that does not include a synchronization signal is input. Terminal 11 is an input terminal into which a sweep signal for sweeping the cathode ray tube 12 in the horizontal and vertical directions is input, and 1 is a cathode ray tube for displaying images.

Next, the operation will be explained.

The oscillator 6 outputs a signal of approximately 3.58 MHz synchronized with the burst signal in the carrier color signal inputted from the input terminal 1, and supplies the signal to the phase controller 5. The phase controller 5 changes the phase of the output signal of the oscillator 6 to a desired value using the control terminal 2, and supplies the signal to the demodulator 7 and the 90° phase shifter 8.

The 90° phase shifter 8 further shifts the phase of the output signal of the phase controller 5 by 90° and supplies the signal to the demodulator 7 . Here, for ease of explanation, the output signal phase of the phase controller 5 is assumed to have a 180'' relationship with the burst signal phase in the carrier color signal input to the input terminal 1, that is, the B-Y axis phase, and is shifted by 90°. The output signal phase of the phase shifter 8 has a 190° relationship with the burst signal phase in the carrier color signal input to the input terminal 1, that is, R
−Y-axis phase.

7. The burst erasing circuit 4 erases only the burst signal from the carrier color signal input from the input terminal 1 using the burst gate pulse input from the input terminal 3, and supplies a chroma signal to the demodulator 7. The demodulator 7 demodulates the chroma signal using the output signal of the phase controller 5 and the output signal of the 90° phase shifter 8 as carrier signals, and supplies B-Y and R-Y color difference signals to the matrix driver circuit 9, respectively. . The matrix driver circuit 9 outputs three primary color signals of R, G, and B based on the luminance signal inputted to the input terminal 10 and does not include a synchronization signal, and supplies the signals to the cathode ray tube 12.

The cathode ray tube 12 receives these three primary color signals and the input signal 11.
A color image is displayed on the screen by the sweep signal input to the monitor.

Through the control terminal 2, the output signal of the phase controller 5, which is the carrier signal of the demodulator 7, and the output signal of the 90° phase shifter 8 maintain a 90° phase relationship with each other, and the carrier color signal inputted to the input terminal 1 is inputted manually. The phase is changed relative to the burst signal phase. The burst signal, which is also a phase reference signal, is a signal modulated with a phase relationship on the -(BY) axis between the R-Y axis and the BY-axis, which are orthogonal to each other, so when demodulating, the burst signal phase is On the other hand, colors faithful to the original signal are reproduced by demodulating using the phase relationship between the RY axis and the BY axis. Therefore, even if the carrier signal of the demodulator 7 is not in the phase relationship of the RY axis and the BY axis with respect to the burst signal phase, it can be easily controlled by the control terminal 2, and the hue can be controlled to a desired hue.

[Problem to be solved by the invention]

Since the conventional hue control device is configured as described above, there is a problem that it cannot be used in a device such as a VTR that does not have a conversion process between a carrier color signal and a color difference signal.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a hue control device that can be used regardless of whether or not there is a conversion process between a carrier color signal and a color difference signal.

[Means to solve the problem]

The hue control device according to the present invention demodulates a carrier color signal into a color difference signal, modulates the color difference signal into a carrier color signal, and
The modulated carrier signal is switched between a fixed phase carrier signal and a variable phase carrier signal in the burst section and the chroma signal section.

Further, in addition to the above, the hue control device according to the second invention further makes the phase control voltage of the variable phase carrier signal the same as the fixed voltage that always determines the phase of the fixed phase carry J signal in the set voltage band. This is how it was done.

[Effect]

In the hue control device of the present invention, when modulating the demodulated color difference signal into the original carrier color signal, in the burst signal section and the chroma signal section, one is a fixed phase carrier signal used during demodulation, and the other is a desired phase carrier signal. By modulating with a variable phase carrier signal that can change the phase of
Hue is controlled by changing the chroma signal phase with respect to the burst signal phase to a desired phase relationship.

Furthermore, if the phase control voltage of the variable phase carrier signal is always the same as the fixed voltage that determines the phase of the fixed phase carrier signal in the set voltage band, the modulated carrier signal phase will be the same regardless of the burst part or the chroma signal part. The phase of the chroma signal with respect to the burst signal of the modulated carrier color signal becomes the same as the phase of the chroma signal with respect to the burst signal of the carrier color signal before demodulation.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a hue control device according to a first embodiment of the present invention. In the figure, 1 is an input terminal into which a carrier color signal is input, 2 is a control terminal for controlling a phase controller 5, and 3 is a switch ( SW) An input terminal to which a burst gate pulse is input to control the circuit 51; 5 is a phase controller that shifts the signal phase by control terminal 2; 6 is a burst in the carrier color signal input to input terminal 1; An oscillator that generates a signal of approximately 3°58MHz synchronized with the signal frequency, 7 is input terminal 1
A demodulator 8 demodulates the carrier color signal inputted to the 3.58 MHz signal, and 8 is a demodulator 90 that shifts the signal phase by 90°.
``The phase shifter 50 converts the signal demodulated by the demodulator 8 into approximately 3
．． A modulator 51 modulates with a 58 MHz signal, and a burst gate pulse input to the input terminal 3 generates an oscillator 6.
52 is an output terminal for outputting the carrier color signal modulated by the modulator 50.

Next, the operation will be explained.

The oscillator 6 outputs a signal of approximately 3.58 MHz synchronized with the burst signal in the carrier color signal inputted from the input terminal 1, and outputs a signal of about 3.58 MHz that is synchronized with the burst signal in the carrier color signal inputted from the input terminal 1.
A signal is supplied to the circuit 51.

The phase controller 5 changes the phase of the output signal of the oscillator 6 to a desired value using the control terminal 2, and supplies the signal to the SW circuit 51. The SW circuit 51 controls the phase controller 5 in the burst signal portion by the burst gate pulse input from the input terminal 3.
The output signal of the oscillator 6 is outputted in other parts.

The carrier color signal input to the input terminal 1 is processed by the demodulator 7.
The output signal of the oscillator 6 and the signal phase-shifted by 90° by the 90° phase shifter 8 are demodulated as carrier signals, and the signals are supplied to the modulator 50.

The modulator 50 is connected to the output signal of the SW circuit 51 and 90@phase shifter 8.
The signal phase-shifted by 90'' is modulated as a carrier signal and the signal is output to the output terminal 52. In the portion other than the burst signal, the output signal of the SW circuit 51 becomes the output signal of the oscillator 6, so the modulator 50 The carrier signal phase of is the same as the carrier signal phase of the demodulator 7. Therefore, the signal output to the output terminal 52 is equivalent to the carrier color signal input to the input terminal 1. Also, in the burst signal part, SW Since the output signal of the circuit 51 becomes the output signal of the phase controller 5, the carrier signal phase of the modulator 50 changes with respect to the burst signal phase in the carrier color signal inputted to the input terminal 1 by the control terminal 2. Therefore, the burst signal output to the output terminal 52 also changes depending on the control terminal 2.

In the carrier color signal, hue is represented by the chroma signal phase relative to the burst signal phase. Therefore, the carrier color signal outputted to the output terminal 52 becomes a carrier color signal whose hue is controlled by the control terminal 2.

In the above embodiment, the SW circuit 51 is controlled to select the output signal of the phase controller 5 only during the burst period, but it may be controlled to select the output signal of the oscillator 6 only during the burst period.

Further, in the above embodiment, a fixed carrier signal is used for the demodulator 7 and a selected carrier signal is used for the modulator 50, but a selected carrier signal may be used for the demodulator 7 and a fixed carrier signal for the modulator 50.

FIG. 2 shows a hue control device according to a second embodiment of the present invention. In the figure, the same reference numerals as in FIG. second and first phase controllers for shifting the phase of the
51 is a modulator that modulates the signal demodulated by the demodulator 7 with a signal of about 3.58 MHz, and 51 is a first phase controller 5a whose phase is controlled by a fixed voltage based on the burst gate pulse input to the input terminal 3. An SW circuit 53 selects one of the output signal and the output signal of the second phase controller 5 whose phase is controlled by the control terminal 2, and the SW circuit 53 is constant when the control voltage of the control terminal 2 is within a certain voltage band. A voltage converter outputs a voltage, 52 is an output terminal that outputs a carrier color signal modulated by the modulator 50, and 54 is a DC voltage source that supplies a fixed voltage v0.

In addition, FIG. 3(a) shows a circuit diagram of the voltage converter of the above embodiment, FIG. 3(a) shows a characteristic diagram of the voltage converter, and FIG.
In a), Tri to Tr5 are transistors, r is a resistor, El and E2 are DC voltage sources, 11 to I3 are DC current sources, r1 to r4 are resistors, and 71 is a first transistor composed of Tr3 and El. Voltage limiter 72 is a second voltage limiter composed of Tr4 and E2, 73 is Trl, Tr2 .
Tr5 and r3. r4 and 11. This is a widely known differential amplifier consisting of I2 and I13.

Next, the operation will be explained.

The oscillator 6 outputs a signal of approximately 3.58 MT (z) synchronized with the burst signal in the carrier color signal input from the input terminal 1, and sends the signal to the first phase controller 5a and the second phase controller 5. The first phase controller 5a supplies a fixed voltage ■.5
4, the input signal phase is shifted to a constant phase, and the signal is supplied to the demodulator 7, the first 90° phase shift circuit 8, and the SW circuit 51.

On the other hand, the second phase controller 5 changes the phase of the input signal from the oscillator 6 to a desired value according to a special voltage obtained from the DC voltage applied to the control terminal 2 by a voltage converter 53, which will be described later. Then, a signal is supplied to the SW circuit 51. SW
In response to the burst gate pulse input from the input terminal 3, the circuit 51 outputs the output signal of the second phase controller 5 in the burst signal portion, and outputs the output signal of the first phase controller 5a in the other portions. do.

The carrier color signal input to the input terminal 1 is processed by the demodulator 7.
The output signal of the first phase controller 5a and the signal whose phase has been shifted by 90 degrees by the first 90'' phase shifter 8 are demodulated as carrier signals, and the signals are supplied to the modulator 50.The modulator 50 The output signal of the SW circuit 51 and the signal whose phase is shifted by 90 degrees by the second 90 degrees phase shifter 8 are interrogated as a carrier signal, and a carrier color signal is outputted to the output terminal 53. Since the output signal of the circuit 51 becomes the output signal of the first phase controller 5a, the carrier signal phase of the modulator 50 becomes the same as the carrier signal phase of the demodulator 7. Therefore, the signal output to the output terminal 52 is equivalent to the carrier color signal input to the input terminal 1. Also, in the burst signal portion, the output signal of the SW circuit 51 becomes the output signal of the second phase controller 5, so the carrier signal phase of the modulator 50 is It changes with respect to the burst signal phase in the carrier color signal inputted to the input terminal l by the control terminal 2.

Next, the operation of the voltage converter 53 will be explained using FIG. 2(a).

The DC voltage applied to the control terminal 2 is applied to the resistor r1 and the resistor r
Tri and Tr2 which are the inputs of the differential amplifier 73 through Tr2
are input into the base of each.

Further connected to the base of Tri are a first voltage limiter 71 that limits the voltage to a constant voltage when the voltage drops below a certain value, and a second voltage limiter 72 that limits the voltage to a constant voltage when the voltage rises above a certain value. has been done. The first voltage limiter 71 is 2.
It is composed of an NPN transistor Tr3 to which TVDC is applied. The emitter voltage of Tr3 is 2.7■. . −
Vll! (Va. is approximately Q, 7Voc), that is, approximately 2.0
Below Voc, it becomes ON state and operates as a limiter, and the voltage is approximately 2°7VEICVll! (That is approximately 2.0Voc
) to limit the emitter voltage to Also, if the emitter voltage is 2.
7Vt+c-■1, that is, at approximately 2.0VDC or higher, the Tr
3 is in the OFF state, and the emitter voltage is not voltage limited. On the other hand, the second voltage limiter 72 is composed of a PNP transistor Tr4 to which 2.4 Voc is applied. Tr
4, its emitter voltage is 2.4Voc+V' It
(V ” st4;! about 0.6vI)c), that is, about 3
．． 0 ■. When it is 8 or more, it becomes ON state and operates as a limiter, and the voltage is 2.4■. C+V'm! (That is about 3.
Limit the emitter voltage to 0Voc). Also, if the emitter voltage is 2. 4 Voc+V'st, that is approximately 3.0V
Below nc, Tr4 is in the OFF state and the emitter voltage is not limited. From the above, the base voltage of Tri is about 3.0VDC when the voltage applied by the control terminal 2 is about 3.0Voc or more, and about 2.0VDC when the voltage applied by the control terminal 2 is about 2.0Voc or less.
Control terminal 2 at 0Voc, 2.0Voc~3.0Vnc
The voltage is almost the same as the voltage applied to . Further, the base voltage of Tr2 is the voltage applied by the control terminal 2, which is 2.
At 0Vbc to 3.0VDC, the voltage is almost the same as the voltage applied to the control terminal, but at about 3.0Vnc or more or about 2
．． When the voltage becomes 0 Voc or less, a difference current generated by the potential difference between the voltage applied to the control terminal 2 and the voltage-limited Tri base voltage and the resistor r1 flows through the resistor r2, so that T
The base voltage of r2 is the voltage applied to control terminal 2 and 1.
A voltage is obtained by superimposing the difference current and the voltage generated by the resistor r2. In this way, the input voltage difference of the differential amplifier 73 becomes almost 0 when the voltage applied to the control terminal 2 is 2.0 to 3.0Voc, and when the voltage applied to the control terminal 2 is 3.0Voc.
Vnc or more or 2°0■. , a difference will appear below. As a result, the output voltage of the differential amplifier 73 is
The characteristics are as follows, and 2.0 to 3.0Vn is applied to control terminal 2.
When c is applied, a constant voltage Vo (Voc) is output.

Now, 2.0 to 3.0■ to control terminal 2. . is added, the second phase controller 5 shifts the phase of the output signal of the oscillator 6 by the control voltage which is the converted voltage of 2.0 to 3.0 Vnc from the voltage converter 53, SW circuit 51
supply a signal to. On the other hand, the first phase controller 5a has a fixed voltage ■. 54 shifts the phase of the output signal of the oscillator 6 to generate S
A signal is supplied to the W circuit 51. As a result, the SW circuit 51
The output signal phase of is in phase with that of the burst signal section and the chroma signal section. Therefore, the chroma signal phase with respect to the burst signal phase of the carrier color signal, which is the output signal of the modulator 50, is the same as the chroma signal phase with respect to the burst signal phase of the carrier color signal, which is the input signal of the demodulator 7.

On the other hand, 2.0■ to control terminal 2. , or less or 3.0VDC
If the voltage above is applied, the voltage converter 53
Due to the characteristics of , the control voltage that controls the second phase controller 5 is the fixed voltage that controls the first phase controller 5a. The value will be different from 54. Therefore, in the output signal of the SW circuit 51, the signal phase at the burst portion is different from the signal phase at portions other than the burst portion. As a result, the chroma signal phase differs from the burst signal phase in the carrier color signal, which is the output signal of the modulator 50, and the hue can be controlled by the control terminal 2 to obtain a desired hue.

In the above embodiment, the SW circuit 51 is controlled to select the output signal of the second phase controller 5 whose phase can be varied only during the burst period, but the first phase controller whose phase is fixed only during the burst period is controlled. Control may be performed to select the output signal of 5a.

Further, in the above embodiment, a fixed carrier signal is used for the demodulator 7 and a selected carrier signal is used for the modulator 50, but a selected carrier signal may be used for the demodulator 7 and a fixed carrier signal for the modulator 50.

Furthermore, the first phase controller 5a is provided with a second voltage converter having the same configuration as the voltage converter 53, and the first phase controller 5a is provided with a second voltage converter having the same configuration as the voltage converter 53.
A fixed voltage 54 may be applied to determine the phase of a.

〔Effect of the invention〕

As described above, according to the hue control device according to the present invention, when modulating the demodulated color difference signal into the original carrier color signal, one of the burst signal section and the chroma signal section has a fixed phase used for demodulation. One carrier signal is used for modulation, and the other is modulated by a variable phase carrier signal that can be changed to a desired phase, so that the output signal becomes a carrier color signal whose hue can be controlled relative to the carrier color signal that is the input signal. This has the advantage that it can be used even in devices such as VTRs that do not have a carrier color signal to color difference signal conversion process. Further, since the control voltage for making the hue of the output carrier wave signal the same as the hue of the input carrier wave signal has a range, there is an effect that the hue can be easily returned to the original hue.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a hue control device according to a first embodiment of the invention, FIG. 2 is a block diagram showing a hue control device according to a second embodiment of the invention, and FIG. 3(a) is a block diagram showing the hue control device according to a second embodiment of the invention. FIG. 3(b) is a circuit diagram of the voltage converter of the embodiment, FIG. 3(b) is a characteristic diagram of the voltage converter, and FIG. 4 is a block diagram showing a conventional hue control device used in a color TV receiver. In the figure, 1, 3, 10, 11 are input terminals, 2 is a control terminal, 4 is a burst canceling circuit, 5 is a phase controller, 5a is a first phase controller, 5 is a second phase controller, 6 is an oscillator, 7 is a demodulator, 8 is a 90° phase shifter, 9 is a matrix driver circuit, 13 is a cathode ray tube, 50 is a modulator, 51 is S
W circuit, 52 is an output terminal, 53 is a voltage converter, 54 is a DC voltage source, 71 is a voltage limiter, 72 is a voltage generator, and 73 is a differential amplifier. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) An oscillating means for generating a signal synchronized with a burst signal frequency in a carrier color signal in a magnetic recording/reproducing device; a phase control means for shifting the phase of a signal generated by the oscillating means; switch means for selecting a signal output by the phase control means; first 90° phase shifting means for shifting the phase of the signal generated by the oscillation means by 90 degrees; a second 90° phase shifting means for shifting the phase of a signal by 90°; a first set of signals including a signal generated by the oscillation means and a signal output by the first 90° phase shifting means; or demodulation means for demodulating the carrier color signal by using one set of signals as a carrier signal of a second set of signals of the signal output by the switch means and the signal output by the second 90° phase shift means; and modulation means for modulating the signal output by the demodulation means into the original carrier color signal by using the other set of signals other than the carrier signal of the demodulation means as a carrier signal. (2) an oscillation means for generating a signal synchronized with a burst signal frequency in a carrier color signal in a magnetic recording/reproducing device; a first phase control means for shifting the phase of the signal generated by the oscillation means; and the oscillation means. a second phase control means for shifting the phase of the signal generated by the second phase control means; a switch means for selecting the signal output by the first phase control means and the signal output by the second phase control means; a first 90° phase shifting means for shifting the phase of the signal output by the first phase control means by 90°; and a second 90° phase shifting means for shifting the phase of the signal output by the switching means by 90°. and a first set of signals of the signal output by the first phase control means and the signal output by the first 90° phase shift means, or a signal output by the switch means and the second set of signals. demodulating means for demodulating the carrier color signal by using one set of signals as a carrier signal of a second set of signals with the signal output by the 90° phase shifting means of the demodulating means; A modulation means modulates the signal outputted by the demodulation means into the original carrier color signal by using the signal as a carrier signal, and a voltage for controlling the phase by the second phase control means is set to a constant voltage within a set voltage band. and voltage conversion means for fixing the phase of the signal output by the second phase control means in the voltage band.