JPH03119870A - Ghost eliminator - Google Patents

Abstract

PURPOSE:To always perform the reception of broadcast satisfactorily by transmitting a discrimination signal to discriminate the presence/absence of the operation of a ghost elimination circuit from an adaptor to a main body, and switching the operating mode of the AGC and APC of a VIF circuit with a transmitted discrimination signal. CONSTITUTION:In the inside of the adaptor 30, a signal from a video input terminal C is supplied to a ghost detection circuit 31, and a detection signal is supplied to the ghost elimination circuit 3. Also, a signal from a control input terminal G is supplied to a comparator 33, and an extracted signal is supplied to the reset terminal of the ghost elimination circuit 3. Furthermore, signals from the ghost detection circuit 31 and the comparator 33 are supplied to an AND circuit 34, and AND output is supplied to a timer circuit 35. A signal from the timer circuit 35 is inverted at an inverter 36, and is supplied to the control terminal of a switch 32, and also, a signal from the timer circuit 35 is directly supplied to the control terminal of a switch 37, and the discrimination signal to discriminate the presence/absence of the operation of the ghost elimination circuit 3 is supplied to a control input/output terminal G.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ghost removal device used in so-called clear vision broadcasting and the like.

[Summary of the invention]

The present invention relates to a ghost removal device, and in the case where the ghost removal circuit is configured as an adapter, by providing a means for transmitting a signal for determining whether or not the ghost removal circuit is in operation from the adapter to the main body, switching of the operation mode in the main body, etc. This makes it possible to easily perform the following steps.

[Conventional technology]

For example, when removing ghosts in clear vision broadcasting, it has been reported that inconveniences will occur if the AGC operation in the VIF circuit and the APC operation of the regenerated carrier used for synchronous detection remain as they are (1989 National Conference of the Television Society). Proceedings〉” P, 249-P, 25
0.11-6. Ghost canceller compatible video IF 1
method study).

In other words, according to this report, V when performing ghost removal
In the IF circuit, ■: Keyed APC where APC is performed during the horizontal synchronization period and sample and hold for one horizontal period ■: Keyed blanking where AGC is held during the vertical synchronization period ■: Transient state when switching channels when the power is turned on It is said that it is necessary to perform continuous/keyed switching etc.

[Problem to be solved by the invention]

By the way, in the above-mentioned ghost removal, it has been considered to separate the ghost removal circuit from the main body of the TV receiver, VTR, etc. and configure it as an adapter. In that case, the operations (1) to (4) described above are performed in the main body in which the VIF circuit is provided.

However, when the ghost removal circuit is configured as an adapter, there are cases where a ghost is not detected from the received signal and the ghost removal circuit becomes inoperable, or where it is forcibly made inoperable by a manual switch or the like. In that case, when the ghost removal circuit is inoperative, the operations (1) and (4) described above are unnecessary and may further cause malfunctions.

However, when the ghost removal circuit is configured with an adapter as described above, it is impossible for the main body to know whether the adapter is operating or not.

It was not possible to switch the operation (2) depending on whether or not the ghost removal circuit was in operation.

This application was made in view of these points, and by providing a means for transmitting a signal for determining whether or not the ghost removal circuit is in operation from the adapter to the main body, it is possible to easily switch the operation mode on the main body. It is intended to do so.

Note that conventionally, designs of VrF circuits, etc. have been considered so that no inconvenience occurs even when the ghost removal circuit is inactive. Furthermore, while it has been considered to transmit a reset signal and the like at the time of channel switching from the main body to the adapter, no consideration has been given to transmitting a discrimination signal from the adapter to the main body.

[Means to solve the problem]

The present invention provides a coast removal device comprising a main body 10) having a tuner (1), a VIF circuit (2), and a video signal circuit (4), and an adapter (30) having a ghost removal circuit (3). A signal from the VIF circuit of the main body is supplied to the video signal circuit of the main body through the ghost removal circuit of the adapter, and a determination signal for determining whether or not the ghost removal circuit is operating is transmitted from the adapter to the main body. means (AND circuit (3)
4) to switches (37)) are provided.

[Effect]

According to this, since a determination signal for determining whether or not the ghost removal circuit is operating is transmitted from the adapter to the main body, the transmitted determination signal is used to control the AGC and AP of the VIF circuit.
It is possible to switch between operating modes such as C, etc., thereby ensuring good broadcast reception at all times.

〔Example〕

In FIG. 1, a signal from an antenna (100) is supplied to a tuner [1] through an antenna terminal A of a main body (10). The signal received by this tuner (1) is V
This VIF is supplied to the input terminal 2A of the IF circuit (2).
The signal from the output terminal 2B of the circuit (2) is taken out to the video input terminal of the main body (10).

The signal from this terminal B is supplied to the video input terminal C of the adapter (30) through the line (20). A signal from this terminal C is supplied to a ghost removal circuit (3), and a signal from this ghost removal circuit (3) is taken out to a video output terminal.

The signal from this terminal passes through the line (40) to the main body (1
0), and the signal from this terminal E is supplied to the subsequent video signal circuit (4).

In addition, a control signal indicating that the channel has been switched from the tuner (1) of the main body (10) is supplied to the control input/output terminal F, and the signal from this terminal F is sent to the control input of the adapter (10) through the line (50). Supplied to terminal G.

Furthermore, in this device, inside the VIF circuit (2), a signal from an input terminal 2A is supplied to a VIF detection circuit (22) through a VIF amplifier (21), and a detected video signal is taken out to an output terminal 2B. Also, VIF7 (
The signal from the APC circuit (21) is supplied to the APC circuit (23) l, and the formed APC signal is taken out to the output terminal 2C, and the signal from the input terminal 2D is supplied to the APC circuit (24).
Second, the signal from this VCO (24) is supplied to the APC circuit (23) to form a phase locked loop. The reproduced carrier signal from this VCO (24) is then supplied to the VIF detection circuit (22). Further, the signal from the VIF detection circuit (22) is supplied to the IFAGC circuit (25), the formed AGC signal is taken out to the output terminal 2E, and the signal from the input terminal 2F is transmitted to the gain of the VIF amplifier (21). Supplied to the control terminal.

Inside the main body (10), the signal from the output terminal 2B of the VIF circuit (2) is supplied to the sync separation circuit (11), and the separated signal is supplied to the horizontal sync pulse generation circuit (12). The signal from the generation circuit (12) is supplied to the APC signal sample and hold circuit (13), and the APC signal supplied from the output terminal 2C to the input terminal 2D is sampled and held. In addition, the signal separated by the synchronization separation circuit (11) is sent to the blanking pulse generation circuit (14).
The signal from this generation circuit (14) is supplied to the AGC
The AGC signal is supplied to the signal sample and hold circuit (15) and sampled and held from the output terminal 2E to the input terminal 2F. This allows APC and AGC in the VIF circuit (2) when performing ghost removal.
Behavior is keyed.

Furthermore, inside the adapter (30), a signal from the video input terminal C is supplied to a ghost detection circuit (31), and this detection signal is supplied to a ghost removal circuit (3). Further, the signal from the control input terminal G is supplied to the comparator (33) through the switch (32), and the extracted signal is supplied to the reset terminal of the ghost removal circuit (3). Further, signals from the ghost detection circuit (31) and the comparator (33) are supplied to an AND circuit (34),
This AND output is supplied to the timer circuit (35).

The signal from this timer circuit (35) is inverted by an inverter (36) and supplied to the control terminal of the switch (32), and the signal from the timer circuit (35) is directly supplied to the control terminal of the switch (37). Ghost removal times through this switch (37) supplied! A signal for determining the presence or absence of the operation (3) is supplied to the control input/output terminal G.

Also, the signal that becomes low voltage when turned off from the manual forced off switch (200) is input to the input terminal H of the adapter (3o).
This signal is supplied to the control terminal of the ghost removal circuit (3) and the AND circuit (34).

As a result, in this device, when a channel switching control signal as shown in FIG. 2 Δ is output from the tuner (1), this signal is sent to the comparator ( 33) to form a reset signal as shown in the same figure. Here, there is a coast detection signal as shown in C in the same figure (high potential), and a forced off switch (20
0) is not operated (high potential), the ghost removal circuit (3) starts operating with a delay time τ after the reset signal, and the operation shown in Figure E is performed (high potential). A discrimination signal is taken out. Further, an AND output as shown in FIG. F is taken out from the AND circuit (34), and when this signal is supplied to the timer circuit (35), a timing signal as shown in FIG. G is generated. Then, during the period when this signal is at a high potential, the switch (32) is turned off and the switch (37) is turned on, and the operation determination signal from the ghost removal circuit (3) is transmitted to the line <50 ).

That is, in this case, the discrimination signal from the ghost removal circuit (3) is transmitted over a period of time T2, which is defined by the timer circuit (35), for example, from time T1 after the fall of the control signal for channel switching.

Therefore, in the above-mentioned device, the main body (10) is provided with a detection circuit (16) that detects the discrimination signal at the above-mentioned timing, and when the detection circuit (16) detects the discrimination signal, the above-mentioned APC and AGC Behavior is keyed.

On the other hand, as shown in the center and right side of the timing chart above, when there is no ghost detection signal and when the forced off switch (200> is operated), the discrimination signal is not transmitted, and therefore the detection Circuit (16
), when no discrimination signal is detected, the sample-and-hold circuits (13) and (15) are set to through mode, and continuous APC and AGC operations are performed.

In this way, according to the above-mentioned device, since the discrimination signal for determining whether or not the ghost removal circuit is operating is transmitted from the adapter to the main body, the operation mode of the VIF circuit such as AGC and APC can be switched based on the transmitted discrimination signal. This allows for good broadcast reception at all times.

In the above-mentioned apparatus, the times T1 and T2 are each, for example, 3QQmsec.

Further, according to the above-described device, there is no risk of adverse effects even if the adapter (30) is connected to a main body that does not have a corresponding circuit.

Furthermore, the above-mentioned device can also transmit a similar determination signal to the power-on control signal transmitted through the line (50).

Furthermore, in the above embodiment, the discrimination signal is transmitted superimposed on the line (50) that transmits the channel switching control signal etc. from the main unit, but this can be done by providing a separate line and transmitting it independently. You can.

〔Effect of the invention〕

According to this invention, the determination signal for determining whether or not the ghost removal circuit is operating is transmitted from the adapter to the main body.
This transmitted discrimination signal allows the VIF circuit to switch between AGC, APC, and other operating modes, thereby making it possible to always receive good broadcasting.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an example of a ghost removal device according to the present invention, and FIG. 2 is a timing chart diagram for explaining its operation. (1) is china, (2) is VIF circuit, (3) is ghost removal circuit, (4) is video signal circuit, (10) is main body, (11) is sync separation circuit, (12) is horizontal sync pulse Generation circuit, (13) is APC signal sample hold circuit, (14) is blanking pulse generation circuit, (15)
is the AGC signal sample hold circuit, (16) is the discrimination signal detection circuit, (20) (40) (50) is the line,
(21) is a VIF amplifier, (22) is a VIF detection circuit,
(23) is the APC circuit, (24) is the VCOl, (25) is the IFAGC circuit, (30) is the adapter, (31) is the ghost detection circuit, (32) and (37) is the switch, (33) is the
) is a comparator, (34) is an AND circuit, (35) is a timer, (36) is an inverter, (100) is an antenna, (200) is a forced off switch, and A-H and 2A to 2F are terminals.

Claims (1)

[Claims] A ghost removal device comprising a main body having a tuner, a VIF circuit, and a video signal circuit, and an adapter having a ghost removal circuit, wherein a signal from the VIF circuit of the main body passes through the ghost removal circuit of the adapter. Ghost removal characterized in that means is provided for supplying a video signal circuit of the main body and transmitting a determination signal from the adapter to the main body for determining whether or not the ghost removal circuit is in operation. Device.