JP3671574B2 - Receiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a receiving apparatus that receives and demodulates transmission signals from a plurality of transmission sources such as terrestrial broadcasting, CATV, and satellite broadcasting.
[0002]
[Prior art]
Currently, satellite broadcasting such as BS (Broadcasting Satellite) broadcasting and analog CS (Communications Satellite) broadcasting is provided in addition to terrestrial broadcasting such as radio and television, and CATV is also performed in some regions. In addition to this, digital CS broadcasting has been carried out due to advances in digital processing technology, digital transmission technology, image and audio compression technology. In the future, the number of digital CS broadcasts is expected to increase. In response, CATV is also being studied in the direction of digitization.
[0003]
These digital broadcasting services include video-on-demand, which allows users to watch programs they want on demand, and near-video-on, where the same program is shifted over a certain time and started on several channels. There are demands, pay-per-view, etc. that are charged for the programs you watch.
[0004]
In these digital broadcasting services, time information is important, and if the time on the transmission side does not match the time on the reception side, inconveniences such as the beginning or end of the program may occur. Therefore, it is considered that time information is multiplexed in a transmission signal transmitted on the transmission side, and a time completely matched with the transmission side is reproduced on the reception side based on the time information.
[0005]
[Problems to be solved by the invention]
In this case, there is no problem as long as there is one transmission side, but it cannot be handled when there are a plurality of transmission sources.
[0006]
An object of the present invention is to execute services on the transmitting side on the receiving side without any trouble even when receiving transmission signals from a plurality of transmitting sources.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, each receiving source has a dedicated clock for each transmission source having time information, and when a certain transmission source is received, the corresponding clock is referred to. Calibration is also performed on the clock for each transmission source.
[0008]
For this purpose, a channel selection signal for receiving one of the plurality of transmission sources as a channel selection transmission source is received, selection means, demodulation means, time information extraction means, first switching means, clock means, A control means for controlling the switching means of 2 and receiving a signal from the control means, selecting a transmission signal of the channel selection transmission source from a plurality of the transmission signals, and selecting a channel including the time information or another channel A selecting means for selecting; a demodulating means for demodulating the signal of the selected channel and reproducing the time information or other information signal; and the time information from the output signal of the demodulating means, and the time information of the tuning transmission source. Time information extracting means for extracting the selected transmission source time information, first switching means for switching the extracted time selection transmission source for each transmission source, and a plurality of clocks prepared for each transmission source, the first switching By means Using the switched time information of the channel selection transmission source, clock means for setting or correcting the clock time of the channel selection transmission source among a plurality of clocks prepared for each transmission source, and for each transmission source A second switching unit that selects a clock of the selected transmission source from a plurality of prepared clocks, and outputs a time for each transmission source; and the other information signal that is an output signal of the demodulation unit is the second Signal processing means for processing using the transmission source time, which is an output signal of the switching means.
[0009]
It is also possible to use time information of a clock for each of a plurality of transmission sources and a transmission source identification signal corresponding to the time information for various signal processing.
[0010]
Therefore, a time information signal of a plurality of clocks prepared for each transmission source in the clock means and / or an identification signal for identifying a transmission source corresponding to each of the plurality of clocks prepared for each transmission source are output. And a second signal processing means for performing signal processing for controlling each means using the time information signal that is an output signal of the time detection means.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
FIG. 1 shows an embodiment of a receiving apparatus that receives a plurality of satellite broadcasts, terrestrial broadcasts, and CATVs. In FIG. 1, 101 is a transmission source for a plurality of satellite broadcasts, 102 is a transmission source for terrestrial broadcasts, 103 is a transmission source for CATV, and 100 is a receiving circuit that receives and demodulates transmission signals transmitted from these transmission sources. is there. In the receiving circuit 100, 104 is a selection circuit, 105 is a demodulation circuit, 106 is a signal processing circuit, 107 is a time information extraction circuit, 108 is a switching circuit, 109 is a clock circuit, 110 is a switching circuit, 111 is a control circuit, and 112 is A tuning signal input terminal, 113 is a time signal external output terminal, and 114 is a demodulated signal external output terminal.
[0013]
This receiving apparatus receives a transmission signal from a transmission source including time information, and uses time information for various services and for improving usability.
[0014]
First, the transmission sources 101, 102, and 103 will be described. The transmission source 101 is a digital CS broadcast, and a plurality of digital CS broadcasts are considered. Time information is multiplexed in a transmission signal transmitted from each transmission source. The transmission source 102 is a terrestrial broadcast. Current terrestrial broadcasts generally do not have time information multiplexed, but the time of terrestrial broadcasts almost coincides with Japan Standard Time. Moreover, the time calibration of the clock using the time signal is still performed. In the future, time information may be multiplexed when terrestrial broadcasting is digitized. The transmission source 103 is a CATV, and along with the digitization of satellite broadcasts, CATV is also being studied in the direction of digitization, including retransmission of satellite broadcasts. Therefore, time information is multiplexed in the transmitted signal.
[0015]
These time relationships of the transmission sources 101, 102, and 103 will be described using FIG. 2 as an example. In FIG. 2, terrestrial broadcasting is considered as a reference. Satellite broadcasting a and b are delayed from terrestrial broadcasting, and the degree of satellite broadcasting b is larger. Conversely, satellite broadcasting z and CATV are more advanced than terrestrial broadcasting, and the degree of satellite broadcasting z is larger.
[0016]
Next, the receiving circuit 100 will be described. A channel selection signal for receiving one of the plurality of transmission sources 101, 102, 103 as a channel selection transmission source is received from the input terminal 102, the control circuit 111 is a selection circuit 104, a demodulation circuit 105, a time information extraction circuit. 107, the switching circuit 108, the clock circuit 109, and the switching circuit 109 are controlled.
[0017]
Upon receiving a signal from the control circuit 111, the selection circuit 104 selects a transmission signal of the channel selection transmission source from a plurality of the transmission signals, and selects a channel including the time information or another channel. The demodulation circuit 105 demodulates the signal of the selected channel, and reproduces the time information or other information signal. The time information extraction circuit 107 extracts the time information from the output signal of the demodulation circuit 105 as time information of the channel selection transmission source. The switching circuit 108 switches the extracted time information of the selected transmission source for each transmission source. The clock circuit 108 has a plurality of clocks prepared for each transmission source, and uses the time information of the selected transmission source switched by the switching circuit 108 to select the clock among the plurality of clocks prepared for each transmission source. Sets or corrects the clock time of the station transmission source. The switching circuit 110 selects the clock of the selected transmission source from a plurality of clocks prepared for each transmission source, and outputs the time for each transmission source. The signal processing circuit 106 processes the other information signal, which is an output signal of the demodulation circuit 105, using the transmission source time, which is an output signal of the switching circuit 110. The transmission source time, which is an output signal of the switching circuit 110, and the demodulated signal processed by the signal processing circuit 106 are output to the outside through external output terminals 113 and 114, respectively.
[0018]
According to the embodiment of FIG. 1, each receiving source has a dedicated clock for each transmission source having time information. When a certain transmission source is received, the corresponding clock is referred to, and time calibration is also performed. Since it is performed for each clock of each transmission source, there is an effect that it is possible to provide a service for each transmission source without any time lag.
[0019]
FIG. 3 shows an embodiment of a method of using the output terminals 113 and 114 of FIG. FIG. 3 shows the recording of a demodulated signal by time reservation. 301 is a demodulated signal input terminal, 302 is a time signal input terminal, 303 is a recording / reproducing circuit, 304 is a timer control circuit, and 305 is a timer setting circuit.
[0020]
The timer setting circuit 305 reserves a time to be recorded in advance. The timer control circuit 304 monitors the time signal input from the input terminal 302 and operates the recording / reproducing circuit 303 when the start time set by the timer setting circuit 305 is reached. When the end time comes, the operation of the recording / reproducing circuit 303 is stopped.
[0021]
By controlling as described above, the operation start and operation end timing of the recording / reproducing circuit 303 can be made completely coincident with the time of the demodulated signal, so that the recording of the demodulated signal is completely performed without being cut off at the start and end portions. There is an effect that can.
[0022]
FIG. 4 shows another embodiment of a receiving apparatus that receives a plurality of satellite broadcasts, terrestrial broadcasts, and CATVs. 4, the same reference numerals as those in FIG. 1 denote the same functions, 401 is a time detection circuit, 402 is a time control circuit, and 403 is a clock circuit. In FIG. 4, in addition to the operation of FIG. 1, time information of a plurality of clocks for each transmission source and a transmission source identification signal corresponding to the time information are extracted from the clock circuit 403 by the time detection circuit 401. Thus, a control signal for controlling each block can be generated and used for various signal processing.
[0023]
As described above, the embodiment of FIG. 4 has an effect that a user-friendly receiving apparatus can be constructed.
[0024]
FIG. 5 shows another embodiment of a receiving apparatus that receives a plurality of satellite broadcasts, terrestrial broadcasts, and CATVs. 5, the same reference numerals as those in FIGS. 1 and 4 indicate the same functions, 501 is a timer setting circuit, 502 is a timer control circuit, and 503 is a maximum delay maximum advance time detection circuit.
[0025]
FIG. 5 is a specific example of the embodiment of FIG. 4 and shows an example of the timer operation of the receiving circuit 100.
[0026]
The timer setting circuit 501 reserves a time to be recorded in advance. On the other hand, the maximum delay maximum advance time detection circuit 503 detects the most delayed delay clock and / or the most advanced advance clock among the plurality of clocks in the clock circuit 403 by using the time detection circuit 401 of FIG. An operation for outputting a time information signal relating to a delay time of the delay clock and / or an advance time of the advance clock and / or an identification signal for identifying a transmission source corresponding to the delay clock and / or a transmission source corresponding to the advance clock; To do. The timer control circuit 502 monitors the time signal output from the maximum delay maximum advance time detection circuit 503, and generates a control signal for controlling each block when the start time and end time set by the timer setting circuit 501 come. And control each block.
[0027]
The above operation will be described with reference to FIG. FIG. 6 shows the relationship between the transmission sources 101, 102, and 103 and the timer operation. For example, the start time is set at 0:00 and the end time is set at 1:00. Here, if the satellite broadcast z is selected as the timer setting transmission source, it is necessary to operate the timer at the time of the satellite broadcast z. That is, in general, it is necessary to operate the timer with the time of the transmission source set in the timer setting circuit 501. Therefore, during timer reservation, it is necessary to wait at the time of the next transmission source to be started. For this purpose, processing such as arranging the reserved time settings in the order of early start is required. Here, in order to simplify these processes, the timer is started at the maximum advance time detected by the maximum delay maximum advance time detection circuit 503, and the timer is ended at the maximum delay time. In the example of FIG. 6, it starts at ts and ends at te.
[0028]
According to this embodiment, it is unnecessary to perform processing such as arranging the reserved time settings in the order of early start, and it is not necessary to wait for the transmission source time to be started next. Furthermore, there is no need to worry about a time lag that occurs when a channel of another transmission source is reserved in continuous time. For example, in the example of FIG. 6, when satellite broadcast z is reserved from 0:00 to 1:00 and then satellite broadcast b is reserved from 1:00 to 2:00, a time lag of T1 + T2 is generated. . Although this idle time may cause the timer operation to react sensitively, there is no such concern in this embodiment. As described above, the embodiment of FIG. 5 has an effect that the processing is simple and a stable timer operation can be expected.
[0029]
FIG. 7 is a specific example of the clock circuit 109 of FIG. In general, even when the clock is different for each transmission source, the time interval is constant and only the phase is shifted. The specific example of FIG. 7 uses this.
[0030]
701 is a time information input terminal for each transmission source, 702 is a difference circuit, 703 is a storage circuit, 704 is an adder circuit, 705 is an output terminal for clock information for each transmission source, 706 is a reference clock circuit, and 707 is a control circuit 111. Is an input terminal for a control signal from.
[0031]
A plurality of clocks prepared for each transmission source in the clock circuit 109 use one reference clock circuit 706, and a difference circuit 702 includes time information of the selected transmission source switched by the switching circuit 108, and the reference clock circuit. The difference from the reference time output from 706 is calculated, and a difference signal is output for each transmission source. The storage circuit 703 stores the plurality of difference signals that are output signals of the difference circuit 702. The adder circuit 704 adds the plurality of stored difference signals, which are output signals of the plurality of storage circuits 703, and the reference time, respectively, and outputs a plurality of addition time signals.
[0032]
According to the embodiment of FIG. 7, since the same effect as a plurality of timepieces can be obtained by using only one reference timepiece, the circuit can be simplified. Needless to say, the example of FIG. 7 can also be used for the clock circuit 403.
[0033]
1, 4, and 5, if there are a plurality of demodulation circuits 105, time calibration processing using the time information extraction circuit 107, switching circuit 108, clock circuit 109 or 403, and other processing are performed. You may perform simultaneously using a separate demodulation circuit.
[0034]
【The invention's effect】
According to the present invention, each receiving source has a dedicated clock for each transmission source having time information. When a certain transmission source is received, the corresponding clock is referred to, and time calibration is also performed for each transmission source. Since it is performed for each source clock, even when transmission signals from a plurality of transmission sources are received, it is possible to execute the services on the transmission side without any trouble on the reception side.
[0035]
It is also possible to use time information of a clock for each of a plurality of transmission sources and a transmission source identification signal corresponding to the time information for various signal processing.
[Brief description of the drawings]
FIG. 1 is a block diagram of a receiving apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram of time information multiplexed on a transmission signal received by the receiving apparatus of the present invention.
FIG. 3 is a block diagram showing how to use the embodiment of the present invention.
FIG. 4 is a block diagram of a receiving apparatus according to another embodiment of the present invention.
FIG. 5 is a block diagram of a receiving apparatus according to another embodiment of the present invention.
6 is an explanatory diagram of time information for explaining the operation of the receiving apparatus of FIG. 5;
FIG. 7 is a block diagram of a main part of a receiving apparatus according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Reception circuit, In the reception circuit 100, 104 ... Selection circuit, 105 ... Demodulation circuit, 106 ... Signal processing circuit, 107 ... Time information extraction circuit, 108 ... Switching circuit, 109 ... Clock circuit, 110 ... Switching circuit, 111 ... Control circuit 112 ... Channel selection signal input terminal 113 Time signal external output terminal 114 Demodulation signal external output terminal 301 Demodulation signal input terminal 302 Time signal input terminal 303 Recording / reproduction circuit 304 Timer Control circuit 305 ... Timer setting circuit 401 ... Time detection circuit 402 ... Time control circuit 403 ... Clock circuit 501 ... Timer setting circuit 502 ... Timer control circuit 503 ... Maximum delay maximum advance time detection circuit 701 ... Time information input terminal for each transmission source, 702... Difference circuit, 703... Storage circuit, 704... Adder circuit, 705. An output terminal of information, 706 ... reference clock circuit, 707 ... input terminal of the control signal from the control circuit 111.

Claims (5)

A transmission signal containing time information is transmitted from each of a plurality of transmission sources, and in a receiving device that receives a plurality of the transmission signals,
A channel selection signal for receiving one of the plurality of transmission sources as a channel selection transmission source is received, a selection unit, a demodulation unit, a time information extraction unit, a first switching unit, a clock unit, a second switching unit Control means for controlling the means;
Selection means for receiving a signal from the control means, selecting a transmission signal of the channel selection transmission source from a plurality of the transmission signals, and selecting a channel including the time information or another channel;
Demodulation means for demodulating the signal of the selected channel and reproducing the time information or other information signal;
Time information extraction means for extracting the time information from the output signal of the demodulation means as time information of a channel selection transmission source;
First switching means for switching the extracted time information of the selected transmission source for each transmission source;
A plurality of clocks prepared for each transmission source, and using the time information of the channel selection transmission source switched by the first switching means, the channel selection among the plurality of clocks prepared for each transmission source Clock means for setting or correcting the time of the clock of the transmission source;
Second switching means for selecting a clock of the selected transmission source from a plurality of clocks prepared for each of the transmission sources, and outputting the time of each transmission source;
Signal processing means for processing the other information signal, which is an output signal of the demodulating means, using the transmission source specific time, which is an output signal of the second switching means;
A receiving apparatus comprising: A transmission signal containing time information is transmitted from each of a plurality of transmission sources, and in a receiving device that receives a plurality of the transmission signals,
A channel selection signal for receiving one of the plurality of transmission sources as a channel selection transmission source is received, a selection unit, a demodulation unit, a time information extraction unit, a first switching unit, a clock unit, a second switching unit Control means for controlling the means;
Selection means for receiving a signal from the control means, selecting a transmission signal of the channel selection transmission source from a plurality of the transmission signals, and selecting a channel including the time information or another channel;
Demodulation means for demodulating the signal of the selected channel and reproducing the time information or other information signal;
Time information extraction means for extracting the time information from the output signal of the demodulation means as time information of a channel selection transmission source;
First switching means for switching the extracted time information of the selected transmission source for each transmission source;
A plurality of clocks prepared for each transmission source, and using the time information of the channel selection transmission source switched by the first switching means, the channel selection among the plurality of clocks prepared for each transmission source Clock means for setting or correcting the time of the clock of the transmission source;
Second switching means for selecting a clock of the selected transmission source from a plurality of clocks prepared for each of the transmission sources, and outputting the time of each transmission source;
First signal processing means for processing the other information signal, which is an output signal of the demodulating means, using the transmission source specific time, which is an output signal of the second switching means;
Time detection for outputting time information signals of a plurality of clocks prepared for each transmission source in the clock means and / or an identification signal for identifying a transmission source corresponding to each of the plurality of clocks prepared for each transmission source Means,
Second signal processing means for performing signal processing for controlling each means using the time information signal that is an output signal of the time detection means;
A receiving apparatus comprising: The receiving device according to claim 2,
The time detecting means detects a delayed clock and / or a most advanced advance clock among a plurality of clocks in the clock means, and relates to a delay time of the delayed clock and / or an advance time of the advanced clock. A receiving apparatus comprising: a time information signal and / or an operation of outputting an identification signal for identifying a transmission source corresponding to the delay clock and / or a transmission source corresponding to the advance clock. The receiving apparatus according to claim 1 or 2,
A plurality of watches prepared for each transmission source in the clock means,
One reference clock means,
A plurality of difference means for calculating a difference between the time information of the channel selection transmission source switched by the first switching means and a reference time output from the reference clock means, and outputting a difference signal for each transmission source; ,
A plurality of storage means for storing the plurality of difference signals, which are output signals of the plurality of difference means, respectively;
A plurality of addition means for adding a plurality of stored difference signals, which are output signals of the plurality of storage means, and the reference time, respectively, and outputting a plurality of addition time signals;
A receiving apparatus comprising: The receiving apparatus according to claim 1 or 2,
Using the transmission source time as an output signal of the second switching means, the recording / reproducing means for recording the output signal of the previous signal processing means or the first signal processing means is controlled. apparatus.

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