JPS5829659Y2 - ghost canceller touch - Google Patents

Description

[Detailed explanation of the invention] The present invention uses a ghost canceller device using the Guivasity reception method, converts a received television signal in the VHF band into a UHF band signal, and further converts this into a received television signal of one empty channel in the VHF band. Convert to John signal,
To provide a system in which the device of the present invention is simply connected to the VHF antenna input terminal of an existing television receiver which selects channels, and the channel selection of each receiving channel is performed by the added device of the present invention.

As is well known, when receiving television broadcast waves, if the target radio waves that arrive directly from the transmitting antenna and the interfering radio waves that arrive after being reflected by reflective objects such as buildings are received at the same time, double waves appear on the TV screen. Image-like interference images, so-called ghosts, occur, making the image extremely unsightly.

As a method for removing such coast interference, the Gui-Bahti reception method as shown in FIG. 1 is effective.

In this method, two receiving antennas A1 and A2 are installed with a slight spatial distance between them, and receive the target radio signals 6° and +6° and the interfering radio waves O1+-ti2, respectively, and both antennas A1. The outputs of A2 61+r>, z- and I
52+62 respectively variable phase shifter 1 and variable attenuator 2
The outputs of both are injected into the combiner 3 to produce a composite ghost signal rJTm, +U275''%, which is minimized by appropriately adjusting the amplitude and phase using the variable phase shifter 1 and variable attenuator 2 described above. This is what happens.

At this time, when there is only one interference wave, a remarkable effect is exhibited, and if a device as shown in FIG. 1 is added to an existing television receiver, images caused by ghosts can be effectively improved.

On the other hand, when multiple channels of TV broadcasting are being carried out in the receiving area, this ghosting is extremely difficult for the receiver, who must adjust the variable phase shifter 1 and variable attenuator 2 every time the receiving channel is changed. It's inconvenient.

For this reason, a preset adjuster 4 is provided as shown in FIG. 1, and the variable phase shifter 1 and variable attenuator 2 can be adjusted in advance for each receiving channel, and each can be optimized for each receiving channel. There is a method configured to preset in a certain state.

However, even in this case, the receiver must select and operate the optimal phase shift amount and attenuation amount for each reception channel set in advance on the preset adjuster 4 at the same time as switching channels on the television receiver. It was extremely complicated.

This proposal has been proposed in light of these shortcomings.
The present invention is configured so that it is sufficient to select one of the unused empty channels (in advance) and select each reception channel switch of the preset adjuster of the proposed ghost canceller device, thereby reducing the complexity of operations for the receiver. It has been resolved.

Furthermore, the present device is constructed so that it can be simply connected to the VHF input terminal of an existing television receiver.

The present invention will be explained below with reference to the embodiments, but for convenience, the same or equivalent parts [U] in each figure are given the same reference numerals.

Figure 2 shows an example in which mechanical channel switching sections 12, 13, 14 are used as in a well-known turret tuner, and Figure 3 shows an example in which a variable capacitance diode is used in the equivalent part as in an electronically tuned tuner. It shows.

Now, in Figure 2, VC, 1ri variable phase shifter, 2ri variable attenuator, 3ri synthesizer, 4 is a preset adjuster, and 4 is a preset adjuster, which is the optimum phase shifter to eliminate ghosts for each receiving channel. Set the amount and attenuation amount ri in advance using this preset adjuster 4 for each receiving channel.
A ghost-free image can be obtained by performing selective operations.

Therefore, as the output from the combiner 3, the output of one selected reception channel in the VHF band is taken out, and this is injected into the conover 2 section 5VC of the next stage.

The converter section 5 includes a high frequency amplifier 6 and a first frequency converter 7
, first local oscillator 8, channel switching section 12.13.1
4, a buffer amplifier 9, a second frequency converter 1o, and a second local oscillator 11.

The high frequency amplifier 6v'i channel switching unit 12 is configured to switch to an amplification frequency corresponding to each reception channel and amplify the signal.

The oscillation frequency of the first frequency converter 7 button and the first local oscillator 8 are also switched according to each receiving channel by the channel switching sections 13 and 141C, respectively.

At this time, the output taken out from the first frequency converter 7 is frequency-converted into one arbitrary UHF band signal and taken out, regardless of which reception channel is switched to.

The UHF band signal output of the first frequency converter 7 is injected into the second frequency converter 1oV'C through the buffer amplifier 9, and converted into one arbitrary VHF band empty channel signal by the second local oscillator 11. and take it out from the output terminal 15.

Therefore, the output terminal 15 of the converter section 5 is connected to a VHF antenna connection terminal of a commercially available VHF HF multi-channel receiver.

In this case, the VHF band signal input fIN injected into the converter section 5 and the VHF band signal output f taken out from the output
The frequency spectrum of OUr must not be reversed.

In order to perform extensive frequency conversion in one go, it is necessary to set the local oscillation frequency f LOCAL "f IN = f OUT, and since f IN and f OUT are both VHF band signals and are close to each other, f LOcAIJj becomes an extremely low frequency. .

If the local oscillation frequency f is selected in this way, f LOCAL
The button SO-rL, in which many harmonics of the button have a frequency close to fIN and fOUT and generate a beat, is large.

To prevent this, the local oscillation frequency fLOcAL should be set to f
LOCAL = f IN + f OUT, but in this case, the frequency spectrum of the signal output f OUT' is inverted with respect to the signal input fI.

Therefore, in the proposed device, the VHF band signal input f is changed to UH once.
The signal is converted to a high frequency in the F band, and this is roughly converted into a signal output fOUT in the I'CVHF band.

Therefore, the signal output f OUT, the first local oscillation frequency fLOCALI, and the second local oscillation frequency fLOcAL2
Relationship with “fOUT” fIN+-hCALI
+fLOCAL2, and these first and second local oscillation frequencies f LOCALI = f LOCAL2\
If both fIN and fOUT are made sufficiently higher, -fLOC
As long as the beat interference between the input and output signals due to ALI=fLOCAL2 falls within the used band, it is eliminated.

Moreover, the first local oscillation frequency fLOCALI and the second local oscillation frequency fLOcAL2ri\ fLOcALI~f
LOCAL2"fOUT-fIN can be arbitrarily selected.

FIG. 4 shows such a relationship for the apparatus according to the present invention, and FIGS. 5 and 6 show its frequency spectrum, with PU video and S representing audio, respectively.

Here, the UHF band signal output of the first frequency converter 7 is:
Since this is an intermediate process for VHF-VHF conversion by the converter section 5, any frequency may be used without being limited to the frequency of the television broadcasting channel in the UHF band, and this frequency spectrum rivHF band signal input f IN
It may be reversed or in the same direction.

In this way, the VHF band television signal is once converted into i arbitrary UHF band signals by the converter section 5, but at this time, the channel switching section 12 of the converter section 5
．． 13. It is configured to work in conjunction with selection switching of each reception channel of the 14tri preset adjuster 4.

Therefore, the television receiver connected to the output terminal 15 of the converter section 5 is connected to the output terminal 15 of the converter section 5.
By selecting and writing an empty channel in the band, there is no need to perform a channel selection operation, and all that is required is a channel selection operation using the preset adjuster 4 of the present device.

FIG. 2 shows an example in which the preset adjuster 4 and the channel switching section 12.13.14 are linked by a mechanical method. For example, the channel switching section 12.13.14
If it is made into a turret type, the same number of changeover switches as the number of reception channels are added to the rotating shaft, and these changeover switches are used as channel selection changeover switches of the preset adjuster 4.

Also, Figure 3 shows an example of linking using an electronic method.
As is well known, the reception channel is selected by the DC voltage applied from the tuning control circuit 16, and each part is controlled simultaneously.

As described above, the present invention works in conjunction with each channel selection switch of the preset adjuster and each channel frequency switch of the converter section, converts a plurality of VHF band television signals into one arbitrary UHF band signal, By roughly converting this into a television signal of an empty channel in the VHF band, the receiver can easily select a channel, and there is no obstacle such as beat interference, and the receiver can receive only the existing VHF band. However, it is possible to connect and view images with ghosts removed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a ghost erasing device using a conventional diversity method, FIGS. 2 and 3 are block diagrams showing a ghost erasing device according to an embodiment of the present invention, FIG. 4 is a block diagram showing the main parts of the present invention, and FIG. , FIG. 6 shows a frequency spectrum diagram of the main part of the present invention. DESCRIPTION OF SYMBOLS 1... Variable phase shifter, 2... Variable attenuator, 3... Combiner, 4... Preset adjuster, 5... Converter part, 6... High frequency amplifier, 7... first frequency converter, 8... first local oscillator, 9... buffer amplifier,
10... Second frequency converter, 11... Second local oscillator, 12, 13° 14... Channel switching section, 15
... Output terminal, 16... Tuning control circuit.

Claims (1)

[Scope of utility model registration request] The Okayama power signal from the two VHF receiving antennas is adjusted to their mutual relative amplitude and phase using a variable attenuator and a variable phase shifter, and then both signals are added together to minimize ghosts. The ghost canceling device according to the method includes: a precent adjuster configured by adjusting in advance the optimum attenuation amount and phase shift amount for each reception channel using the variable attenuator and variable phase shifter and selectively switching these; The VHF band television signal output is obtained, amplified, frequency-converted to an arbitrary UHF band signal, and then frequency-converted to a television signal of an empty channel in the VHF band.
a converter section that switches the amplification frequency and the local oscillation frequency of the first frequency conversion according to the channel of the F-band television signal; At the same time, connect the selected TV receiver to an empty channel in the KVHF band outputted from the converter section, and switch each reception channel of the VHF band by simply switching the channel of each reception channel of the preset adjuster. A ghost canceling device characterized by a signal scale that eliminates the ghost of the receiving channel.