DE1487086C - Color television receiver circuit for automatic compensation of the color saturation errors caused by residual detuning - Google Patents

Description

1 sheet of drawings

Claims (1)

1 2 The invention relates to a color television receiver Fig- 1 an intermediate frequency transmission curve of the circuit for automatic compensation of the color television receiver and F i g. 2 circuit arrangement according to the invention,
saturation error with one of the frequency discriminations in FIG. 1 reproduced amplifier characteristic for frequency adjustment of the tuner. A color saturation image carrier at point A at 38.9 MHz, and the color carrier in the curve to the chrominance signal is determined by the ratio of the luminance level of 4.43 MHz. If the device point A 'is faulty at 34.47 MHz. The amplitude ratio adjustment result from disturbance of this in decibels of the image or color carrier determines the signal ratio then errors in the color saturation io degree of color saturation. If the receiver is misaligned, the image reproduction is correspondingly untrue. For example, in the direction of point B for the image carrier, an automatic control of the image carrier is known, - ie the upper frequencies in the down color saturation depending on the amplitude distortions occurring on the projection of 5.5 MHz from the image carrier are weakened with corresponding » blunt «image (USA.-Patent 2,851,518), for which not 15 reproduction -, the color carrier migrates to the curve point B ', which is only required very complex circuit arrangements on the right, so that this is also similar, but also the use of a particularly weakened and the color saturation is falsified, the unusual special tube of which is proposed. In the other case of image carrier misunderstanding, it is also known that, for color saturation control towards curve point C, the high image frequencies are reproduced in an amplified manner depending on the amplitude ratio of the peak values of 20 with correspondingly "sharp" color or line synchronizing signals. The color carrier moves here to use voltage, by sifting out one of the right-hand side of the characteristic to point C "and harmonics from the line sync pulse, is amplified compared to its normal position with which, after selective and from the image reversal, the corresponding error in the color sensor gain is rectified, for which 25 saturation. complex switching arrangements are also required. According to FIG. 2, only minimal switching is required (German patent 1,258,450). Also from the line expenditure this return pulse from a residual detuning Keyed amplifier stages automatically compensate for touching color saturation errors another approach (German patent 1,198,411), siert. The color television signal comes from the residence For automatic color saturation control, a 30 antenna 1 on channel selector 2 for UHF or VHF amplifiers of the color channel through .from its areas and arrives at the IF amplifier 3. An Output signal-dependent control voltage controlled, the IF amplifier 3 is a frequency discriminator 4 and a separate color blocking stage connected to the generation which is based on the image intermediate frequency of special switching voltage is used. 38.9 MHz is tuned. For this frequency-after all It is known that the color saturation discriminator 4 is the oscillator of the channel control a control voltage obtained from the phase selector 2 readjusting DC voltage, discriminator of the reference oscillator for control. According to the invention, the same control voltage is used of the amplifier stage for the brightness signal to ent- a voltage divider 5, 6 connected via which the take, i.e. at a point where the control voltage is dependent on the corresponding polarity the detuning supplies a voltage curve, 40 removed, via resistor 7 to the grid of which a more or first amplifier stage 9 is fed in the area of interest, to which via has less broad maximum. The gradient of the curve capacitor 8 is also supplied with the chrominance signal. is so low here that the control sensitivity is un- This kind of the grid of the amplifier stage 9 for the remains satisfactory. . The control voltage supplied to the chrominance signal is compensated In contrast, the invention is based on the object, according to the invention, by residual detuning to increase the control sensitivity significantly, in caused saturation errors and creates autodem the zero-metric supplied by the tuner discriminator a saturation of the color image. The control point voltage With a steep S-shaped voltage, you can use the variable resistance voltage curve and depending on the understanding 6 can be adjusted, creating a good com tune is used. 5 ° compensation can be achieved over a large detuning range To achieve automatic compensation of goals is.
Color saturation errors by means of a control DC voltage taken from the frequency discriminator for the patent claims-tuner tuning, is identified
the invention in that this DC voltage 55 Via a voltage divider the grid of the chrominance 1. Color television receiver switch to the car signal amplifier stage is fed. matic compensation of the color saturation errors caused by residual detuning automatic color saturation control with small one from the Freqiienzdiskriminator for Remaining detuning of the tuner obtained by the discriminator in 60 frequency adjustment Tuners tuned to the frequency in color control DC voltage, thereby marked television receiver be guaranteed by the records that this DC voltage is above Color saturation in each case to the optimal value a voltage divider (5. 6) the grid of the remains put. Chrominance signal amplifier line (9) is supplied. The essence of the invention is based on an illustration. fülirungsbeispieles described in the drawings, claim I, characterized in that the namely shows resistor (6) of the voltage divider can be controlled.