JPS60260281A - Color television receiver - Google Patents

Abstract

PURPOSE:To simplify an externally mounted circuit to an IC by providing a switching circuit turning on an output transistor (TR) of a PAL/NTSC chrominance carrier signal and an output TR of an SECAM chrominance carrier signal only at the reception of PAL and SECAM signal. CONSTITUTION:The switching circuit 15 turning on the output TR1 of the PAL and SECAM chrominance carrier signal only at the reception of PAL is provided in an IC1 for processing PAL/NTSC colors. Moreover, the switching circuit 17 turning on the output TR2 for the SECAM chrominance carrier signal only at the reception of SECAM is provided in an IC5 for processing the SECAM color signal. Then a 1H delay circuit 12 is connected between an output terminal connected in common with the TR1, TR2 and each input terminal of the IC1 and IC5, and an output of color demodulation circuits 3, 4 and color demodulation circuits 9, 10 is extracted selectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a color television receiver capable of receiving PAL signals, NT8C signals, and SFICAM signals.

(B) Prior Art As a color signal processing unit for a television receiver as described in the introduction, the present applicant previously proposed a circuit configuration as shown in FIG. 3 in Utility Model Application No. 59-3972.

That is, in FIG. 3, [11 is the 11C (M5 made by Mitsubishi Electric Corporation)
1385P, etc.), and the carrier color signal of PAL and WT day C (PAL: 4.43MHz, NTS C: 3.5
8MH2) band amplification circuit (2), B-Y, R
-Y In addition to each corner circuit f31f41, it is provided with an Arc % ACC, a color killer circuit, a PAL twisting circuit, a PAL switch circuit, etc. attached thereto. (5) is SP
A second IC (M51398P manufactured by Mitsubishi Electric Corporation, etc.) for CAM color signal processing, and a limiter amplifier circuit (6) for amplifying the SICAM carrier color signal, which is provided via a direct path (Ll) from the amplifier circuit. A non-delayed carrier color signal and a carrier color signal input from the outside via the terminal (T7) are transferred to two output paths (I, z) (Ls) for IH (one horizontal period).
EllICAM switch circuit (7) that distributes and derives signals for each, a switch control circuit (8) that controls the switching operation of this switch circuit by obtaining a horizontal pulse (HP) and a signal (from), BY, R-Y Each demodulation circuit (9) flo
Because it is equipped with l, etc.

On the other hand, (o) PAL signal, NTSG signal, smc
This is a signal path selection circuit that switches a signal path for a carrier color signal in response to each reception of an AM signal, and is configured as follows. That is, the buffer transistor (TR
\PAL carrier color signal appearing on its emitter and second IC
+51) Terminal (T6) K j Switching diode (Dl) for selectively switching and outputting derived SFCAM carrier color signals (D%) Each carrier color signal passes through a coupling capacitor (C2) for impedance matching. resistor (R1) and coil (LC) K, the IH delay line 01J is inputted, the carrier color signal passing through this delay line and the coupling capacitor ( A transformer Ll performs addition/subtraction of the carrier color signal given through C3) and separates it into a B-Y carrier color signal and a R-Y carrier color signal, and each of the signals is transferred to the 11th C
Line leading to color demodulation circuit +31+41 in (1) (
Ls) (R4), and a coupling capacitor (C4) for guiding the carrier color signal that has passed through the delay line Q2 to the terminal (T7')K of the second IC (5).

In addition, 04 is each demodulation circuit +31+4) or 191f
This is a switching circuit for guiding the B-Y signal and R-Y signal output from the IO) to the color matrix circuit, and this switching circuit is built into the IC in the aforementioned C:M51398F, but here it is For convenience, external components are shown as circuits.

In addition, the PAL of the band amplification circuit 12) in No. 11C(1)
Switching of the passband between reception and NTBC reception is performed by switching constants of an external tuning circuit.

Further, switching of the same wave number of the subcarrier signal applied to the demodulation circuit 1B+[41 in this IC is performed by switching an external crystal oscillator. Furthermore, when receiving NTSC, this I
Stop the switching operation of the PAL switch circuit in C and
The constant phase subcarrier signal for TSC is sent to the above demodulation circuit +3
I am trying to give it to 041. Such 1st IC (
Since the configuration in 1) is already known, further explanation will be omitted.

Now, while the circuit in Figure 3 is busy, the first switching terminal (Pl
) is applied with a high level (B) voltage only during PAL reception, and a low level () voltage is applied during other receptions.On the other hand, conversely, a low level (B) voltage is applied to the second switching terminal (P2) during PAL reception. A high level is applied, and an H level is applied during other receptions. Therefore, when receiving PAL, a diode (Ds
) (Ds) is turned on and the diode (D2) is turned off, so that the PAL carrier color signal output from the terminal (T1) of the first section C11) is on the one hand connected to the transistor (T
R) emitter → diode (Dl) → capacitor (C
2)→IR delay line (lη) is applied to the primary side of the transformer (1), and on the other hand, the above transistor (TR
) → Point A → The capacitor (C6) is applied to the intermediate tap on the secondary side of the transformer (1 turbidity), so the IH delayed and non-delayed PAL carrier color signals are added and subtracted on the secondary side. As a result, the B-Y carrier color signal is distributed to the line (Us) and the R-Y carrier color signal is distributed to the line (LJ).At this time, since the diode (D3) is on, the carrier color signal is distributed to the line (Us) and the R-Y carrier color signal to the line (LJ). The resistance value of the variable resistor (VR) with respect to the signal becomes equivalently small, and the non-delayed signal applied to the intermediate tap on the secondary side of the transformer (11) is stepped down from the primary side and appears on the secondary side. The signal is adjusted to approximately the same magnitude as the delayed signal.

Also, when receiving N'l'SC, the diode (Dl) (Ds
) turns off, the NT8C carrier color signal appearing at the point A passes only through the path of the capacitor (C3) and is applied to the intermediate tap on the secondary side of the transformer (1 step), and from there to the line (:t, n ) (Ls). At this time, the resistance value of the variable resistor (VR) becomes equivalently larger due to the diode (Ds) being turned off, and the signal at point A becomes equal to the value at the time of PAL reception. The width is adjusted to approximately twice the thickness, thereby making it possible to derive a carrier color signal having approximately the same size as when receiving the PML on the line (LJ) (ILs).

Next, when receiving SICAM, the diode (D2) is turned on and the diodes (Dt) (Dg) are turned off, so the 8FC output from the terminal (T6) of the second ICIb)
AM carrier color signal is transferred from diode (D2) to capacitor (C
2) → IH delay line (12) → capacitor (C → terminal (
81 of the second IC (5) through the route of T7)! icAM
Switch circuit (7) K input, from here B-Y.

This means that it is distributed and derived from the R-Y can transport color signal.

By the way, in this conventional circuit, the lH delay is 4!珀をPAL
Can be used for both SFtCAM and Pmu"1"-"
QO$ship 9 non-1 immediately 5°yf:y-f(Csゝ3) to N
It has the advantage that it can be shared for TBC, but the transformer (
11, a buffer transistor (TR), three switching diodes (Ds) (D2) (Ds), etc., and the external installation of the circuit C has the disadvantage that the circuit is complicated and cannot be realized at low cost.

Purpose of the Invention The present invention has been made in view of the above points, and in realizing a television receiver capable of receiving color television signals of each of the above-mentioned systems, it is possible to use an IC other than an IC for color signal processing. The purpose of this is to simplify the circuit as much as possible and realize it at low cost.

B) Structure of the Invention In the color television receiver of the present invention, FAI, /N
PAIJ in the 11th C for TSC color signal processing
and a first switching circuit that turns on a first output transistor to which the NTSC carrier color signal is received only when AL reception is received; A carrier color signal distribution circuit is provided in which the other carrier color signal input is inputted from the outside through the 11C input terminal, and the IIIEICAM color signal is inputted in the second IC for 811ICAM color signal processing. Input transmission color signal output transistor 2, 81 A second switching circuit that is turned on only when receiving CAM, and the above-mentioned 81! ICA
A SIII CAM switch circuit is provided, in which an M carrier color signal is provided as one input via a direct path in the second IC, and the other carrier signal input is provided externally via an input terminal of the second IC, Furthermore, a KIH delay circuit is connected between the commonly connected output terminals of the first and second output transistors and each of the input terminals of the first and second ICs. and a first one to which the output signal of the carrier color signal distribution circuit is applied.
Each output signal of the color demodulation circuit in the 1C and the color demodulation circuit in the second IC to which the output signals from the 8FiCAM switch circuit are applied is selectively taken out.

(E) Embodiment FIG. 1 shows a schematic configuration of the main parts of an embodiment of the present invention. Parts corresponding to those in FIG. explain. That is, in this embodiment, first, in the first section C1L for PAL/NTBC color signal processing, a band amplification circuit (2) and a demodulation circuit (3) (4) similar to those in FIG. ), a first switching circuit (16, a first output transistor (TR1), and a carrier color signal distribution circuit +IT@) is provided. N.T.
Switches the S Cx (operates in response to the signal (R8) K and increases the gain of the output signal of the band amplifier circuit (2)), and turns on the first output transistor (TR1) for deriving this output signal. , it is set to turn off. Further, the carrier color signal distribution circuit (one wheel has an addition circuit and a subtraction circuit, and the PAL or NTSC carrier color signal from the first switching circuit +1m is directly routed (L6) as an input to each of the two circuits. The other carrier color signal input is applied from outside the unit C through the terminal (T12).

The output signal of the adder circuit is transmitted to the line (L7) in the IC.
) to the B-Y demodulation circuit (3), and the output signal of the subtraction circuit is input to the R-Y demodulation circuit (4) by the line (L8).
).

Here, the first killer voltage (K1) is the 11th C+1)
PAL spanning NT8 in color killer circuit (not shown)
The G signal is generated by detecting the presence or absence of the strike signal. Further, the NT8C switch signal (N8') is a signal indicating whether the received signal is an MTBC signal or not, and is provided via a manual selection switch provided outside the IC or a detection circuit for horizontal and vertical scanning frequencies. ing. Oh,
Of course, circuits such as circuits and FAL switch circuits are also provided in the first section C(1), similar to those shown in FIG.

Next □, Ell! 2nd IC for IcAM color signal processing
In (6), a second switching circuit ano is added that turns on and off the second output transistor (TR1) for deriving the output signal of the limiter amplifier circuit (6) in response to the second killer voltage (K2). The configuration is the same as that in Figure @3 except for the following.

In the present embodiment, the first and second ICs (5) are configured as described above, and the first and second output tries of the emitter-follower configuration are
The output terminals (T11) (71s) connected to
C) and the input end of the IH delay line α, and the output end of this delay line is connected to the second X through a coupling capacitor (C4).
A slider of a variable resistor (TR2) for adjusting the amplitude of the delayed output connected to the input terminal (T16) of C(5) and connected to the output side of the delay line [1fi] is connected to the coupling capacitor (C6).
) is connected to the input terminal (T12) of the 11th Ctl). Note that % (LC) is a coil for adjusting the delay time.

Now, in this embodiment, when receiving PjlkL, the second
As shown in the figure, the first killer electric current FE (Ki) is at H level, and the NTEIC switch signal (MS) is at L level.

As a result, the first switching circuit (In is the band amplifier circuit (2)
At the same time, the gain of the PAL carrier color signal from the output terminal is substantially attenuated, and the first output transistor (TRI) is turned on to output the attenuated PAL carrier color signal to the output terminal (T11).
Derive K. At this time, the second killer voltage (K2) reaches the knee level, so that the second switching circuit (+71) turns off the second output transistor (TR2), but in this state both transistors (TR+) (TR2) are common. Since it is connected to the emitter, it is reliably achieved.The PAL carrier color signal derived from K to the output terminal (T11) is 1
■The non-delayed carrier color is inputted to the carrier color signal distribution circuit fllK in the delay line (lfi, then passes through the input terminal (T12) to the 11th C+1), and is input to this circuit directly via the path (L6). B- divided by addition and subtraction with the signal
Demodulation circuit fS corresponding to each Y%R-Y carrier color signal
)(+) respectively, it becomes K.

Next, when receiving NTBC, the first killer voltage (K1) and the NT8C switch signal (R8) both reach the KH level as shown in FIG. As a result, the first switching circuit (1) does not attenuate the gain of the N78G carrier color signal from the band amplifier circuit (2), and also turns off the first output transistor (TR1). At this time, the second killer voltage ( K2) becomes L level, and the second output transistor (TR2) is also turned off in accordance with the amount of PAL reception.As a result, the first switching circuit (
Only the HTEJC carrier color signal passing through the direct path (L4) from I@ is input to the distribution circuit (l-, and therefore the 11th C+1
The demodulation circuit in 1 [31 (4) has the same N T B, C
The carrier color signal is input with substantially the same magnitude as when receiving 'PAL.

Furthermore, when receiving 8FICA, the first killer voltage (K1) and the NT8C switch signal (K8) go to L level, so the first output transistor (TRI) is turned off, and conversely, the second killer voltage (K2) is turned off. Level 2
Since the output transistor (TR2) is turned on, the 21st
811f appearing at the output terminal ('I'+s) of c(5)
After the CAM carrier color signal passes through the IH delay line (1), it passes through the input terminal (Tt6) to 81!iC in the second xc (5).
Since it is input to the AM switch circuit (7), the third
As in the case shown in the figure, the signals are divided into the B-Y carrier color signal and the R-Y carrier color signal, and each signal is sent to the demodulation circuit t9H.
This is the translation given to 11.

Furthermore, the first and second killer voltages (K1) (K2) are also input to the carrier color signal distribution circuit (l→ and the switch control circuit (8) K, respectively, and when they are at L level, the above-mentioned circuits (
11+81 operations are respectively stopped.

(f) Effect of the invention According to the present invention, FAI, %NT day C, 811 ICAM
In creating a television receiver that can receive television signals of various formats, externally attaching a color signal processing IC allows the circuit to have a very simple configuration with a small number of components, making it possible to reduce costs. It has the advantage of being achievable.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing the schematic configuration of the main parts of an embodiment of the present invention, Fig. 2 is a diagram used to explain its operation, and Fig. 3 shows the schematic structure of the main parts of a conventional color television receiver. It is a circuit diagram. (1): 11th C, K51: 2nd IC, (TR1): 1st output transistor, (Tug door 27.2 output transistor, a = IH delay circuit. Applicant: Sanyo Electric Co., Ltd. Representative Patent Attorney Shizuo Sano

Claims (1)

[Claims] +1) PAL signal, 1iTBc signal, and EIFICAM
A television receiver capable of receiving a signal from a P.A.
PAL is included in the first IC for L/NT8C color signal processing.
and NTS (!) A band amplification circuit for amplifying a carrier color signal, a first switching circuit that turns on a PAL reception path for a first output transistor into which the output signal of the amplification circuit is input, an addition circuit and a subtraction circuit. a carrier, wherein one input end of the two circuits is connected to the output side of the band amplification circuit via a direct path in the 11C, and the other input end is connected to the carrier color signal input terminal of the 11C. A color signal distribution circuit and a color demodulation circuit for demodulating each carrier color signal from the distribution circuit are provided, and the second IC for SFiCAM color signal processing includes an S
A VC input/output carrier color signal amplification circuit amplifying circuit, and a second output transistor to which the output signal of the amplifying circuit is input.
S: [! a second switching circuit that is turned on only when receiving IcAM, one input end of which is connected to the output side of the limiter amplifier circuit via a surface path in the second IC, and the other input end of which is connected to the output side of the limiter amplifier circuit; sNl connected to the input terminal
An ICAM switch circuit and a color demodulation circuit for demodulating each carrier color signal from the switch circuit are provided, and the commonly connected output ends of the first and second output transistors and each carrier color signal of the first and second IC are provided. I between input terminal
A color television receiver in which an H delay circuit is connected, and the output signals of each color demodulation circuit in the first and second ICs are switched and taken out. (2) Both of the first and second output transistors have an emitter-follower type structure, and their respective emitters are mutually connected to the IT.
1. A color television receiver according to claim 1, wherein the color television receiver is commonly connected to the input terminals of the slow-wave circuit. (3) The color according to claim 81, characterized in that the first switching circuit switches to derive a carrier color signal having a size twice that of the PAL reception path to the direct path during NT8G reception. television receiver.