KR970004921Y1 - Pal plus receiving system - Google Patents

Abstract

None.

Description

ARM Plus Receiving System

1 is a block diagram of a conventional arm plus receiving system

2 is a block diagram of the arm plus receiving system according to the present invention

3 is a detailed configuration diagram of the helper killer of FIG.

4 is a signal waveform diagram of FIG.

* Explanation of symbols for main parts of the drawings

11: Tuner 12: External input line

13: buffer 14: helper demodulator

15 subcarrier frequency generator 16 phase shifter

17, 19, 22, 25: clamp portion 18, 24: delay portion

20: sand cast signal generator 21: comparison unit

23: helper marker signal generator 26: signal bit detector

27: helper killer SW11-SW 15: switch

The present invention relates to an arm plus (PAL PLUS) receiving system, and more particularly to an arm plus receiving system to carry a color burst signal to increase the stability of the signal and to improve the compatibility with the existing TV by placing a helper killer.

The Arm Plus system is a new European terrestrial broadcasting standard and is an EDTV (Extend TV) system compatible with existing arm systems. FIG. 1 shows a block diagram of a conventional Arm Plus receiving system.

The Composite Video Bass Signal (CVBS) Arm Plus Receive Plus signal configuration contains Signaling Bits on line 23 to convey information about the Arm Plus, lines 24-59, 275-310, 336-371, 587-622 contain AM helper signals locked on the U axis about the subcarrier frequency fsc.

Here, the U axis refers to the color difference signals RY and BY in the TV signal, respectively, the V axis and the U axis. When AM modulation is performed by fsc, the V axis (RY) is shifted by + 90 ° relative to the U axis (BY). Modulate.

The CVBS signal is transmitted through the AM demodulator 2 in the subcarrier frequency generator 3 through the luminance (hereinafter referred to as Y) separator 1, and the U (BY) signal through the low pass filter LPE1. It is input to the terminal a of the switch SW1.

The CVBS is also input to the terminal b of the switch SW1 through the Y separating section 4 and the clamp section 5.

High is output only in the helper signal line section, and during the helper signal section, the switch SW1 is switched to the terminal a so that the AM helper demodulation signal is output. Otherwise, the pure Y signal is transmitted through the terminal b of the switch SW1. Is applied to the Super (S) -VHS VCR.

On the other hand, the color (hereinafter referred to as C) signal is input to the terminal b of the switch SW2 through the band pass filter BPF1 and the clamping part 6, and the terminal a of the switch SW2 is grounded. It is.

During the helper signal section, the switch SW2 is switched to the terminal a so that the C component is not applied to the S-VHS and the section C outside the helper signal section separates the terminal b of the switch SW2. Is applied to the S-VHR VCR.

However, the conventional technique as described above does not consider the delay relationship between the demodulated helper signal and the existing CVBS signal, and carries only the demodulated signal on the helper signal in the switching process to carry the demodulated helper signal during the helper signal period. The signal is not included.

Therefore, it is difficult to control the phase of the subcarrier frequency locked to the U-axis when the VCR is remodulated by the AM helper signal.

In addition, when a tape recorded as a helper signal demodulated with a helper signal is reproduced in a normal VCR, the helper signal demodulated at 4: 3TV is input to the TV, so that the color signal is not processed in black at the helper section (letter box), and the color signal is irregular. There is a disadvantage to be dealt with.

The present invention is to solve this problem, and an object of the present invention is to provide a one-arm plus receiving system to provide a color burst signal to the demodulated helper signal to prevent phase shift during playback.

Another object of the present invention is to set up a Helper Killer device to maintain compatibility with existing TVs and VCRs, and to process the arm plus signal so that the arm plus signal does not affect the video signal. In providing.

A feature of the present invention for achieving the above object is the arm plus receiving system carrying a helper signal, the demodulation unit for performing a pulse-type demodulation of only the helper signal at a color carrier frequency by using the arm plus signal carrying the helper signal as an input signal; A helper signal processing means comprising a level adjuster for adjusting a helper signal demodulated by a demodulator to a constant level, an output suppressor for suppressing a helper signal output that is an output signal of the level adjuster, and an arm plus signal carrying the helper signal; A signal matching means composed of a time delay unit and a level adjusting unit so as to produce an output time and an output level equal to the output signal of the helper signal processing means; A switching means composed of a plurality of switching sections for switching and outputting an arm plus signal carrying a helper signal; And a bit detector for detecting a signal bit using the arm plus signal carrying the helper signal as an input signal, and a helper marker generator for generating a high signal and outputting a high signal at a predetermined interval of the arm plus signal carrying the helper signal. An arm plus receiving system comprising control means for controlling the means.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a block diagram of the present invention, which includes a switch SW2 for switching the tuner 11 input and an external input line 12 and a buffer 13 for buffering the output of the switch SW2. The bandpass filter BPF11 and the helper demodulator 14 demodulating the helper signal after bandpass filtering the signal, and locking the phase of the output signal of the buffer 13 at a subcarrier frequency and shifting the phase to perform the helper demodulator. A subcarrier frequency generator 15 and a phase shifter 16 input to 14, and an amplifier AMP11 and a lowpass filter LPF11 for amplifying the output of the helper demodulator 14 and then lowpassing it. ), A clamp unit 12 for clamping the output of the low pass filter LPF11, and a delay unit 18 for delaying and clamping the output signal of the buffer 13 by the signal delay during the helper demodulation and low pass filtering. ), (24) and clamps (19), (25), and the buffer (13) A sand cast signal generator 20 for generating a sand castal signal using a power output; a comparator 21 for generating a high blanking signal using the sand cast signal; A switch SW12 for switching the outputs of the clamp units 17 and 19 using the high blanking signal of 21 as a switching signal, a helper marker signal generator 23 for generating a helper marker signal, and the switch; A switch SW13 for switching the clamping output signal of the SW12 and the output signal of the clamp unit 25 according to the helper marker signal, and the presence or absence of an arm plus signal by detecting a signal bit from the buffer 13 output signal. A signal bit detector 26 for outputting a signal, a switch SW14 for switching and outputting the output of the switch SW13 and the buffer 13 output signal using the output of the signal bit detector 26 as a switching signal; Providing a helper killer signal to the clamp unit 17 It consists of the helper killer part 27.

As shown in FIG. 3, the clamp unit 17 is connected to the transistors TR1 and TR2 that switch according to an input signal, and the emitter side of the transistors TR1 and TR2 to clamp the clamping pulse CLP. Transistor (TR3) for clamping the input signal at the time of input, and a variable resistor (VR1) connected to the base end of the transistor (TR2) to adjust the clamping DC level, the helper killer (27) is manually When the helper killer is connected to the slide switch SW15 for generating a helper killer signal, the switching transistors TR4 and TR5 which are turned on when the slide switch SW15 is turned on, and the collector terminal of the transistor TR5, It is composed of a variable resistor VR2 for adjusting the DC level.

The present invention configured as described above switches the signal received from the tuner 11 and the signal input from the external input line 12 to the tuner high signal in the switch SW11, and the signal passed through the switch SW11 is buffered ( 13), the CVBA carrying the arm plus signal filters the frequency band of the AM-modulated helper signal with the subcarrier frequency in the band pass filter BPF11.

The AM-modulated helper signal is input to the helper demodulator 14, and the subcarrier frequency (4.43 MHz) signal whose phase is locked is output from the subcarrier frequency generator 15 to which the CVBS is input. Go through).

In addition, since the signal may be delayed while the helper signal passes through the band pass filter BPF11, the phase shifter 16 controls the phase of the subcarrier frequency.

On the other hand, the helper demodulator 14 performs a balanced demodulator using a multiplexer to demodulate a helper signal that is balanced and modulated at a subcarrier frequency like the C signal.

Since the signal output from the helper demodulator 14 is very weak, it is amplified by the amplifier AMP11. Since the balanced demodulated signal includes various unnecessary high frequency components, unnecessary components are removed through the low pass filter LPF11. do.

Since the frequency band of the helper signal is about 3.5 MHz, the low pass filter LPF11 allows the cutoff frequency to be 3.5 MHz.

The demodulated helper signal passing through the low pass filter LPF11 is input to the clamp unit 17. The clamp unit 17 fixes the DC level of each signal having a different pedestal level and the variable resistor VR1. Use the switch SW12 to adjust the required DC level.

And the helper signal is loaded at 300mV AC based on the black level (Fig. 4), which is used to implement the helper signal based on the black level so that it can be processed as black even when received from the existing 4.3TV. It was.

When the signal is demodulated, as shown in FIG. 4 (b), the DC level is 350mV and the AC 300mV signal is loaded.

Therefore, the signal demodulated by the switch SW12 is switched with the existing CVBS signal, and the helper signal is input to the clamp unit 21 through the delay unit 20.

The signal delay is generated while the helper signal passes through the band pass filter BPF11, the helper demodulator 14 amplifier AMP11, the low pass filter LPF1, and the clamp unit 17. Since the filter BPF11 and the low pass filter LPF11 are the main factors of the delay, the delay unit 20 is provided.

In addition, the sand cast signal generator 18 generates a high blanking signal through the sand caster signal generated using the CVBS signal through the comparator 19 (Fig. 4 (C)), and switches the high blanking signal. The demodulated helper signal at the high blanking signal high time is superimposed on the helper signal of FIG. 4A using the switching signal of SW12.

In addition, since the color burst signal disappears when the helper signal is demodulated, the switch SW12 switches with the CVBS through the delay unit 20 because the color burst signal is required during recording and playback in the VCR.

The color burst of this signal is again recorded separately at Y / C in the VCR, and is necessary to control the subcarrier frequency phase when modulating the helper signal to the subcarrier frequency during reproduction.

On the other hand, since the demodulated helper signal carried in the composite video signal is input to the switch SW13 via the clamp unit 22, the normal signal of the section line without the helper signal is also demodulated and switched by the switch SW12. Since the existing normal signal needs to be restored, the switch SW13 switches to the helper marker signal from the helper marker signal generator 23.

The helper marker signal generator 23 makes the helper marker signal high in the line sections 24-59, 275-300, 336-361, and 587-610 on which the helper signal is loaded, and inputs the helper marker signal to the switch SW13.

During this period, the demodulated helper signal is switched to the existing CVBS and loaded.

The switch SW14 selects the demodulated helper signal and the normal signal according to the presence or absence of the arm plus signal, and the switch SW14 carries the CVBS from the buffer 13 through the signal bit detector 26 on the line 23rd. The signal bit is detected and an arm plus signal is output in accordance with the detected signal.

Accordingly, the arm plus signal demodulated through the switch SW14 is separated into Y and C in the S-VHS VCR and recorded on the tape.

On the other hand, the helper killer unit 27 that is not described above is described as follows.

First, when the demodulated helper signal is input to the clamp unit 17 through the low pass filter LPF11, the input signal is clamped by the clamping pulse CLP input to the transistor TR3, and the clamping point is colored. Burst part.

Since the DC level of the demodulated helper signal for each clamping DC level adjustment point is 350m, the DC bias level is adjusted using this variable resistor VR1.

In addition, the transistors TR4 and TR5 are operated during the helper killer, and the transistors TR4 and TR5 are turned on when the helper killer slide switch SW15 is manually turned on.

The transistor TR4 prevents the demodulated helper signal passing through the low pass filter LPF11 from being passed to the rear end, and the transistor TR5 is operated to adjust the DC level when the helper killer is operated by the variable resistor VR2.

When the helper killer is operated, the signal input to the switch SW12 is removed and only the DC level is input. When the helper signal is deleted from the helper signal of FIG. 4A, only the maximum black level remains.

Since the black level is 300mV, it is changed by the variable resistor VR2 to adjust the DC bias level input to the switch SW12 to 300mV.

As described above, the present invention incorporates a color burst when recording an arm plus broadcast on an S-VHS VCR to increase the stability of the signal during playback and maintains the compatibility with existing TVs. By avoiding the effect, a clearer image can be obtained.

Claims (2)

An arm plus receiving system carrying a helper signal, comprising: a demodulator for balanced demodulation of only a helper signal at a color carrier frequency using the arm plus signal carrying the helper signal as an input signal; and a helper signal demodulated by the demodulator to a predetermined level. An output signal of the helper signal processing means, comprising a helper signal processing means comprising an level adjusting unit for adjusting, an output suppressing unit for suppressing a helper signal output which is an output signal of the level adjusting unit, and an arm plus signal carrying the helper signal as an input signal; A signal matching means composed of a time delay unit and a level adjusting unit so as to have an output time and an output time and an output level such as an output signal, an output signal of the signal processing means, an output signal of the signal matching means, or an arm prus signal carrying the helper signal. A switching means composed of a plurality of switching parts for switching output, and an arm plus scene carrying the helper signal; A high-rank generator for outputting a high-rank signal with a call as an input signal, a bit detector for detecting a signal bit using the arm plus signal carrying the helper signal as an input signal, and a constant arm plus signal carrying the helper signal; Arm plus receiving system, characterized in that consisting of a control means for controlling the switching means is composed of a helper marker generating unit for generating a high signal in the section. The arm plus receiving system according to claim 1, wherein the high rank generating unit comprises a sand caster generating unit and a comparing unit.