GB2268346A - Add-on means for tuning VCR or satellite receiver output away from channel 5 - Google Patents
Add-on means for tuning VCR or satellite receiver output away from channel 5 Download PDFInfo
- Publication number
- GB2268346A GB2268346A GB9213536A GB9213536A GB2268346A GB 2268346 A GB2268346 A GB 2268346A GB 9213536 A GB9213536 A GB 9213536A GB 9213536 A GB9213536 A GB 9213536A GB 2268346 A GB2268346 A GB 2268346A
- Authority
- GB
- United Kingdom
- Prior art keywords
- output
- input
- eliminator
- signal
- satellite receiver
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/76—Television signal recording
- H04N5/765—Interface circuits between an apparatus for recording and another apparatus
- H04N5/775—Interface circuits between an apparatus for recording and another apparatus between a recording apparatus and a television receiver
- H04N5/7755—Interface circuits between an apparatus for recording and another apparatus between a recording apparatus and a television receiver the recorder being connected to, or coupled with, the antenna of the television receiver
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/41—Structure of client; Structure of client peripherals
- H04N21/4104—Peripherals receiving signals from specially adapted client devices
- H04N21/4112—Peripherals receiving signals from specially adapted client devices having fewer capabilities than the client, e.g. thin client having less processing power or no tuning capabilities
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/445—Receiver circuitry for the reception of television signals according to analogue transmission standards for displaying additional information
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/47—End-user applications
- H04N21/488—Data services, e.g. news ticker
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
Abstract
New Channel 5 has been assigned to the frequency channel 36 which is currently used for VCRs. The tuning range of VCRs is insufficient to return them clear of channel 36 and other transmissions. The add-on device changes the frequency (by modulating onto the new frequency) of either the VCR or the satellite receiver (leaving room for returning of the VCR close to the vacated satellite channel) by means of a turnable modulator 51. <IMAGE>
Description
INTERFERENCE ELIMINATOR
This invention relates to an interference eliminator for eliminating interference between television channels in certain circumstances.
In current UK standards for the operation of video cassette recorders and satellite receivers, the video cassette recorder is set at channel 36 and the satellite receiver output is set at channel 38. The range of other channels in use at the present time extends from channels 23 to 33, which channels are used for normal atmospheric transmissions such as those from the two BBC and the two ITV channels. In order to avoid interference between the channels, it is necessary that the channels, which represent certain frequencies, be spaced two channels apart. Thus the atmospheric transmission channels which end 33 are spaced 3 channels from the video cassette recorder channel at 36 and in turn the video cassette recorder channel is spaced 2 channels from the satellite receiver channel at 38.In order to set the appropriate channels of the video cassette recorder and the satellite receiver, each of these pieces of equipment are provided with tunable modulators normally tunable in the range of channels 30 to 39. Thus the present available transmissions are catered for without interference.
However, a new television channel is shortly being introduced (called Channel 5) and this has been allocated a transmission channel of 36. It therefore follows that the new channel will be the same as that usually used for the video cassette recorder and thus the two signals will be superimposed. An obvious solution to this problem would be to retune the video cassette recorder, but the maximum to which this could be re-tuned would be to channel 39 which, while avoiding interference with the new Channel 5, would be too dose to the setting for the satellite receiver channel at 38 and interference between the video cassette recorder and the satellite receiver would ensue.In order, therefore to solve this problem, it would, at the very least, be necessary to replace the tunable modulator in either the video cassette recorder or the satellite receiver to enable one or other of these to be re-tuned to a channel above that of the current maximum of 39.
Such a change might well be of considerable expense and, in certain circumstances, it might be necessary to replace the entire piece of equipment.
The present invention seeks to provide an interference eliminator which enables the above problem to be reduced or substantially obviated while not requiring any modification of either the video cassette recorder of the satellite receiver.
According to the invention, there is provided an interference eliminator comprising a tunable modulator of a desired frequency range, means for connecting an input of the modulator to the output of a satellite receiver or video cassette recorder and output means providing an output from the modulator, the arrangement being such that the modulator converts the output signal of the satellite receiver or video cassette recorder to a channel within the desired range.
Preferably the eliminator is used in connection with a satellite receiver and is connected to the output thereof, the eliminator output being connected suitably, in the usual way, to the video cassette recorder.
Additionally, the eliminator may be provided with an input connected to the line between the satellite dish and the satellite receiver and incorporate means for extracting a power supply from this cable for operation of the interference eliminator. It will be understood that the cable between the satellite receiver and the satellite dish normally carries a supply voltage of between 13 and 18 volts which is used to operate the low noise downblock converter provided in the satellite dish. In these circumstances the eliminator is provided with an input and an output for the satellite dish cable, the satellite signal being arranged to bypass the eliminator while the supply voltage is supplied to a voltage regulator to provide the desired voltage for the operation of the eliminator.
As an input to the eliminator, the eliminator may be connected to the audio and video output from the satellite receiver, the eliminator also being provided with an aerial input for atmospheric transmissions and an output providing the combined signal from the atmospheric aerial and the satellite receiver.
The eliminator may be arranged to transmit the signal from the atmospheric aerial with only amplification while the audio and video signals from the satellite receiver are converted to within a channel range provided by the eliminator.
In a variation of the interference eliminator, it could be provided at the output of the video cassette recorder instead of at the output of the satellite receiver, the signals from the atmospheric aerial and from the satellite receiver being passed unaltered, except for possible amplification, but the video cassette recorder signal being modulated into the tuning range of the eliminator.
The invention will now be described in greater details, by way of example, with reference to the drawings, in which:
Figure 1 is a schematic view of the normal connection arrangements of television, video cassette recorder and satellite receiver;
Figure 2 is a view similar to Figure 1 but showing the positioning of an interference eliminator in accordance with the invention;
Figure 3 is a perspective view of an interference eliminator in accordance with the invention, and
Figure 4 is a block circuit diagram of an interference eliminator in accordance with the invention.
Referring firstly to Figure 1, there is shown diagramatically the connections for a standard set-up which comprises a television set 1, a video cassette recorder 3, a satellite receiver 5, an atmospheric aerial 7 and a satellite dish 9. As can be seen, the satellite dish 9 is connected to the satellite receiver 5 by a cable 11. The atmospheric aerial 7 is also connected to the satellite receiver 5 by a cable 13 and the output of the satellite receiver is connected to the video cassette recorder 3 by means of a cable 15.
The satellite receiver 5 is such that the output 15 cable contains both the received satellite signal tuned to an appropriate channel and the signal from the atmospheric aerial 7 unaltered but possibly amplified to some extent. The video cassette recorder then has it's output connected by a cable 17 to the television set 1.
This is of course an entirely suitable arrangement under the present circumstances. The signals being received by the atmospheric aerial 7 have allocated to them channels 23 to 33 while the satellite receiver is suitably tuned to channel 38 and the video cassette recorder is tuned to channel 36. In these circumstances all of the used video channels are separated by at least 2 channels and in this way there is no significant interference between the different channels.
The problem arises with the advent of the new Channel 5 which has been allocated a frequency of channel 36, this being the same as that normally used by the video cassette recorder. Both the video cassette recorder and the satellite receiver have within them modulators which are normally tunable between channels 30 and 39+ thus making it impossible to have two channels, one for the video cassette recorder and the other for the satellite receiver which are spaced by at least 2 channels from each other and from the signals received by the atmospheric aerial which will then extend up to Channel 36.
In order to overcome this problem, it is necessary to be able to reset the channels allocated to the video cassette recorder and/or the satellite receiver above the presently usable range and this would involve at least the replacement of the modulator in the video cassette recorder of the satellite receiver, this being an expensive and relatively complicated procedure. There may even be some cases in which the entire piece of equipment would need to be replaced.
In order to overcome this problem an interference eliminator, in accordance with the invention, may be used. Figure 2 is a view similar to Figure 1 showing the use of a interference eliminator which, for example, has a tuning range which extends significantly above the tuning range present in either the video cassette recorder or the satellite receiver. Thus the eliminator may be arranged to be tunable between channels 30 and 45 or, for simplified production purposes, channels 40 to 49. As can be seen from Figure 2, the interference eliminator 21 in accordance with the invention is connected so as to modify the output of the satellite receiver 5.To this end, the eliminator 21 is provided with an input cable 23, (see also Figure 3), which is connected to the output of the satellite receiver 5 and is provided with an output socket 25 connected by the cable 15 to the video cassette recorder 3. The atmospheric aerial 7 is connected by it's cable 13, not to the satellite receiver, but to an input 27 on the eliminator. The cable 11 from the satellite dish 9 is split into two portions 11A and 11B, the portion 11A connecting the satellite dish 9 to the eliminator 21 while the portion 11B connects the eliminator 21 to the satellite receiver 5.To this end, the eliminator 21 is provided with a first socket 29 for connection to the satellite dish 9 via the cable portion 11A and a second socket 31 for connection via the cable portion 11B to the satellite receivers.
As will be appreciated, because of the very high frequency, of the order of 11 GHz, at which the satellite transmits signals, it is necessary to transform the signals to about 1.1GHz in order that they can be satisfactorily transmitted from the satellite dish 9 to the satellite receiver 5 using normal cables. To this end, the satellite dish 9 is provided with a low noise downblock converter (not shown) and this requires the provision of a supply of voltage, which can be varied, suitably between 13 and 18 volts, for switching purposes and this supply is bled off within the interference eliminator 21 to provide power therefor.
In operation of the interference eliminator, this is suitably tuned to channel 44 providing a channel 44 output from the satellite receiver 5. Then the video cassette recorder 3 can be reset to use channel 39 and, in this way, both the video cassette recorder and the satellite receiver avoid interference with the new TV channel on channel 36.
Figure 4 shows a basic block diagram of the interference eliminator 21. In this figure, it can be seen that power supply is taken from the satellite dish lead 11, the two cable portions 11A and 11B being connected at terminals 29 and 31 to a power regulator 41 which incorporates a bypass for the satellite dish signal while extracting supply voltage therefrom. A blocking device (not shown) is provided which prevents the input of the satellite dish signal into the interference eliminator 21. The power regulator 41 is required to convert the variable supply voltage of between 13 and 18 volts into the 9 volts required by the eliminator. The output of the satellite receiver 5 is connected via the cable 23 which has a video line 43 and an audio line 45 as is usual with satellite receiver outlets.The signal on the video line 43 is passed to a video matching circuit 47 which is associated with an audio matching circuit 49 to which the audio input line 45 is connected. The output of both the video matching circuit 47 and the audio matching circuit 49 are fed to a radio frequency modulator 51 which combines the audio and video signals into a combined video signal and modulates this into a radio frequency signal at the frequency of channel 44. This modulator is, of course, variable and can, for example, be tuned in the range of channel 30 to channel 45 or possibly other ranges such as channel 40 to channel 49.Into the RF modulator 51 are also fed the signals from the atmospheric aerial 7 by means of an input socket 27, this signal being combined with the radio frequency modulated signal derived from the satellite receiver, but, apart from a certain amplification, being otherwise unmodified. The eventual output signal then appears on the output socket 25. From this output socket 25, the signal is passed to the usual input socket (commonly called the "aerial input socket") of the video cassette recorder 3.
From the foregoing, it will appreciated that by the simple provision of the interference eliminator in accordance with the invention and with only the subsequent retuning of the video cassette recorder, the problem created by the new Channel 5 can be substantially removed without any interference with the units of the set-up themselves.
Although the provision of the interference eliminator in the output line of the satellite receiver has been described, it will be appreciated that the interference eliminator could be provided in the output line of the video cassette recorder. In this case, of course, it would be the channel of the output of the video cassette recorder which would be changed, the channel of the satellite receiver remaining within it's original range, but adjusted, if necessary, within that range. In these circumstances, the atmospheric aerial could be connected to the the satellite receiver or to the interference eliminator as required.
It will also be appreciated that various modifications can be made to the above described embodiments without departing from the scope of the invention. For example, although the interference eliminator has been described as using the power supply available from the satellite dish cable, it could also use any other supply which might be available. It could be provided with it's own power supply either connected to the mains or by means of a battery.
It will also be understood that while the particular embodiment have been directed towards solving the problem caused by the advent of the new Channel 5, it could equally well be used in circumstances where a signal available from apparatus at a certain frequency or frequency range requires to be transformed to a different range or frequency without interference with the particular piece of apparatus concerned and is particularly useful in cases where a number of outputs need to be combined, only some of which need to have their frequencies of frequency ranges altered.
Claims (12)
1. An interference eliminator comprising a tunable modulator of a desired frequency range, means for connecting an input of the modulator to the output of a satellite receiver or video cassette recorder and output means providing an output from the modulator, the arrangement being such that the modulator converts the output signal of the satellite receiver or video cassette recorder to a channel within the desired range.
2. An interference eliminator system comprising an interference eliminator as claimed in claim 1, wherein the eliminator is connected to the output of a satellite receiver and to a video cassette recorder.
3. An interference eliminator system as claimed in claim 2, wherein the eliminator is provided with an input connected to the line between the satellite dish and the satellite receiver and incorporates means for extracting a power supply from this cable for operation of the interference eliminator.
4. An interference eliminator system as claimed in claim 3, wherein the eliminator is provided with an input and an output for the satellite dish cable, the satellite signal being arranged to bypass the eliminator while the satellite dish supply voltage is supplied to a voltage regulator to provide the required voltage for the operation of the eliminator.
5. An interference eliminator system as claimed in claims 2, 3 or 4, wherein the eliminator is connected to the audio and video output from the satellite receiver, the eliminator also being provided with an aerial input for atmospheric transmissions and an output providing a combined signal from the atmospheric aerial and the satellite receiver.
6. An interference eliminator system as claimed in claim 5, wherein the eliminator comprises means for transmitting the signal from the atmospheric aerial with only amplification and means for converting the audio and video signals from the satellite receiver to within a channel range provided by the eliminator.
7. An interference eliminator system comprising an interference eliminator as claimed in claim 1, wherein the eliminator is connected to the output of a video cassette recorder and comprises means for transmitting signals from an atmospheric aerial and from a satellite receiver unaltered, except for amplification, and means for modulating the signal of the video cassette recorder signal into the tuning range of the eliminator.
8. An interference eliminator substantially as described herein with reference to the drawings.
9. An interference eliminator system substantially as described herein with reference to the drawings.
Amendments to the claims
have been filed as follows 1. An interference eliminator in the form of a self contained unit for eliminating interference between channels in a television set up comprising a first input for connection to a first high frequency signal source consisting either of the output of a satellite receiver or a video cassette recorder, a second input for connection to a second high frequency signal source other than that connected to the first input, an output providing an output from the unit, a tunable modulator for connection between the first input and the output for changing the channel frequency of the signal from the first input into a channel in a desired frequency range and connection means for connection of the second input with the output without modulation of the signal from the second input, the arrangement being such that the modulator converts the output signal of the satellite receiver or video cassette recorder to a channel within the desired frequency range and a signal is provided at the output of the unit which combines the modulated signal from the first input with the unmodulated signal from the second input.
2. An interference eliminator system comprising an interference eliminator as claimed in claim 1, wherein the first input of the eliminator is connected to the output of a satellite receiver and the output of the unit is connected to a video cassette recorder.
3. An interference eliminator system as claimed in claim 2, wherein the eliminator is provided with a further input connected to the line between the satellite dish and the satellite receiver and incorporates means for extracting a power supply from this cable for operation of the interference eliminator.
4. An interference eliminator system as claimed in claim 3, wherein the eliminator is provided with the said further input and a second output for the satellite dish cable, the satellite signal being arranged to bypass the circuitry of the eliminator while the satellite dish supply voltage is supplied to a voltage regulator to provide the required voltage for the operation of the eliminator.
5. An interference eliminator system as claimed in claims 2, 3 or 4, wherein the eliminator is connected by its first input to the video output from the satellite receiver and by another input to the audio output of the satellite receiver, and the second input of the eliminator is an aerial input for atmospheric transmissions and the output of the eliminator provides a combined signal from the atmospheric aerial and the satellite receiver.
6. An interference eliminator system as claimed in claim 5, wherein the said connection means of the eliminator comprises means for transmitting the signal from the atmospheric aerial with only amplification and means, including the tunable modulator are provided for converting the audio and video signals from the satellite receiver to a channel within the desired frequency range provided by the eliminator.
7. An interference eliminator system comprising an interference eliminator as claimed in claim 1, wherein the first input of the eliminator is connected to the output of a video cassette recorder and the second input receives signals from an atmospheric aerial and oom a satellite receiver, the connection means transmits the signals from the atmospheric aerial and the satellite receiver unaltered, except for amplification, and the tunable modulator modulates the signal of the video cassette recorder to convert the channel frequency thereof into a channel within the desired frequency range.
8. An interference eliminator system for eliminating interference between channels in a television set up comprising an interference eliminator in the form of a self contained unit including a first input connected to the output of a satellite receiver, a second input connected to an atmospheric aerial, an output providing an output from the unit and connected to a video cassette recorder, a tunable modulator for connection between the first input and the output for changing the channel frequency of the signal from the first input into a channel in a desired frequency range and connection means for connection of the second input with the output without modulation of the signal from the second input, the arrangement being such that the modulator converts the output signal of the satellite receiver to a channel within the desired frequency range and a signal is provided at the output of the unit which combines the modulated signal from the first input with the unmodulated signal from the second input.
9. An interference eliminator system for eliminating interference between channels in a television set up comprising an interference eliminator in the form of a self contained unit including a first input connected to the output of a satellite receiver, a second input connected to an atmospheric aerial, a third input connected to the satellite dish, a first output providing an output from the unit and connected to a video cassette recorder, a second output connected to the input of the satellite receiver, a tunable modulator for connection between the first input and the output for changing the channel frequency of the signal from the first input into a channel in a desired frequency range, connection means for connection of the second input with the output without modulation of the signal from the second input and voltage supply means connected between the third input and the second output for bypassing the satellite signal from the circuit of the eliminator and supplying the satellite dish supply voltage to the eliminator circuitry as a power supply, the arrangement being such that the modulator converts the output signal of the satellite receiver to a channel within the desired frequency range and a signal is provided at the output of the unit which combines the modulated signal from the first input with the unmodulated signal from the second input.
10. An interference eliminator system for eliminating interference between channels in a television set up comprising an interference eliminator in the form of a self contained unit including a first input connected to the output of a video cassette recorder, a second input connected to an atmospheric aerial and the output of a satellite receiver, an output providing an output from the unit, a tunable modulator for connection between the first input and the output for changing the channel frequency of the signal from the first input into a channel in a desired frequency range and connection means for connection of the second input with the output without modulation of the signal from the second input, the arrangement being such that the modulator converts the output signal of the video cassette recorder to a channel within the desired frequency range and a signal is provided at the output of the unit which combines the modulated signal from the first input with the unmodulated signal from the second input.
11. An interference eliminator substantially as described herein with reference to the drawings.
12. An interference eliminator system substantially as described herein with reference to the drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9213536A GB2268346B (en) | 1992-06-25 | 1992-06-25 | Interference eliminator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9213536A GB2268346B (en) | 1992-06-25 | 1992-06-25 | Interference eliminator |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9213536D0 GB9213536D0 (en) | 1992-08-12 |
| GB2268346A true GB2268346A (en) | 1994-01-05 |
| GB2268346B GB2268346B (en) | 1996-01-17 |
Family
ID=10717740
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9213536A Expired - Fee Related GB2268346B (en) | 1992-06-25 | 1992-06-25 | Interference eliminator |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2268346B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2385473A (en) * | 2002-02-04 | 2003-08-20 | Novapal Ltd | Tuning a set-top box output to an allocated TV channel |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4514757A (en) * | 1980-07-03 | 1985-04-30 | Alps Electric Co., Ltd. | CATV selection device |
| EP0176824A1 (en) * | 1984-09-14 | 1986-04-09 | Deutsche Thomson-Brandt GmbH | Circuit arrangement for frequency-changing for a television receiver |
| EP0224900A2 (en) * | 1985-12-03 | 1987-06-10 | Tino Giuseppe Motta | Radio frequency switching, regulation, amplification and/or attenuation system |
-
1992
- 1992-06-25 GB GB9213536A patent/GB2268346B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4514757A (en) * | 1980-07-03 | 1985-04-30 | Alps Electric Co., Ltd. | CATV selection device |
| EP0176824A1 (en) * | 1984-09-14 | 1986-04-09 | Deutsche Thomson-Brandt GmbH | Circuit arrangement for frequency-changing for a television receiver |
| EP0224900A2 (en) * | 1985-12-03 | 1987-06-10 | Tino Giuseppe Motta | Radio frequency switching, regulation, amplification and/or attenuation system |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2385473A (en) * | 2002-02-04 | 2003-08-20 | Novapal Ltd | Tuning a set-top box output to an allocated TV channel |
| GB2385473B (en) * | 2002-02-04 | 2005-11-30 | Novapal Ltd | Apparatus for receiving broadcasts |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2268346B (en) | 1996-01-17 |
| GB9213536D0 (en) | 1992-08-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19980625 |