JP2008160207A - Information distribution system, its method, transmitter, and receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information distribution system for transferring information in a plurality of levels by a pilot signal, its information distribution method and a transmitter/receiver used for the information distribution system. <P>SOLUTION: This information distribution system is configured to transmit multi-level information inputted from an input terminal 17 from a transmitter 1 to a receiver 14 by using a pilot signal. This information distribution system is characterized by making a pilot signal output part 8 generate a plurality of predetermined synchronizing different frequency pilot signals, and by selecting two pilot signals as the difference of a frequency or the difference of the number of cycles corresponding to the information quantity of the multi-level information, and by transmitting the pilot signals from a signal transmission part 4 to the receiver 14. The receiver 14 is provided with a means 11 for extracting the two pilot signals at each frequency and an information output part 13 for outputting the multi-level information corresponding to the difference of the frequency or the difference of the number of cycles from the two extracted pilot signals to an output terminal 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an information distribution system for transmitting multilevel information using a pilot signal in an information distribution system for superimposing and transmitting a pilot signal, an information distribution method for the information distribution system, and a transmitter and a receiver used in the information distribution system. .

  In addition to broadcasting to conventional VHF / UHF band analog TV, various TV broadcasting services such as BS broadcasting, CS broadcasting, and terrestrial digital broadcasting have become available in individual houses or apartment houses. In these cases, there are a CATV format in which a broadcast signal is individually received by an antenna as a direct wave for viewing and a CATV format in which a radio frequency is distributed by a cable such as an optical fiber and received by a home TV tuner.

  In the case of the CATV format using the latter optical fiber, the broadcast wave is transmitted from the transmitting device to the subscriber device with the radio frequency as it is, or when the radio frequency is high, converted to an intermediate frequency and optically modulated and transmitted. The radio frequency distribution signal OE converted at the subscriber's home is directly input to the corresponding broadcast wave tuner terminal, so that the television can be viewed.

  In a broadcast wave signal for transmitting a distribution signal by a broadcast wave, a pilot signal is inserted and used as a synchronization signal or reception control of a multiplexed signal. The pilot signal is inserted individually with respect to, for example, a terrestrial digital signal and a BS / CS signal.

  In systems that optically transmit broadcast wave signals, the reception device monitors the reception quality of radio broadcast signals and device failures, and monitors the reception quality and device failures of wireless broadcast signals at relay devices. Accordingly, it is necessary to transfer alarm signals to the devices in the system all at once.

  For example, in the conventional technology for transferring alarm signals, in two-way communication composed of a pair of fiber cables, a pilot signal with a fixed period is superimposed on the data in the form of an optical signal on the fiber cable and transmitted. Describes a method in which the optical devices at both ends can be known even in the case of a one-side fiber failure by prohibiting transmission for a certain period of time when the no-signal state continues (see, for example, Patent Document 1). However, only one level, such as whether or not there is a fiber break, can be transferred, notifying multiple levels to indicate the degree of transmission quality, notifying transmission path failures and device failures, etc. Multi-value information with an amount of information suitable for the alarm signal could not be transferred.

In another conventional technique, an optical carrier wave having a wavelength different from the wavelength of the main signal light is used for transferring the monitoring control information (for example, see Patent Document 2). However, in order to notify a plurality of levels for indicating the degree of transmission quality, or to notify a plurality of information such as a transmission path failure and a device failure, it is necessary to prepare an optical carrier dedicated to an alarm signal. In spite of the fact that the amount of information required is not required, an optical carrier dedicated to alarm signals must be prepared.
JP-A-5-276123 JP 2003-249899 A

  As described above, conventionally, multilevel information cannot be transferred by simple transfer using a pilot signal. In the present invention, in order to solve such a problem, an information distribution system capable of transferring multi-value information by a simple transfer method using a pilot signal, the information distribution method, a transmission device and a reception device used in the information distribution system The purpose is to provide.

  The present invention achieves the above-mentioned object, and is an information distribution system for transmitting multilevel information from a transmitting apparatus to a receiving apparatus using a pilot signal, and the frequency difference or the number of cycles of pilot signals of two different frequencies The difference is transferred as the amount of multi-value information.

  An information distribution system according to the present invention is an information distribution system that transmits multilevel information from a transmission device to a reception device using a pilot signal, and the transmission device includes pilots having a plurality of predetermined synchronized different frequencies. A pilot signal output unit that generates a signal and selects and outputs two pilot signals having a frequency difference corresponding to the information amount of the multi-level information; and the pilot signal output from the pilot signal output unit to the receiving device A signal transmitting unit for transmitting, and the receiving device receives a pilot signal transmitted by the signal transmitting unit, and a frequency detecting unit for detecting a frequency of a pilot signal received by the signal receiving unit. An information output unit that calculates a difference between the frequencies detected by the frequency detection unit and outputs the multi-value information having an information amount corresponding to the difference. It is characterized in.

  Since the frequency difference between the pilot signals of two different frequencies is transmitted as the information amount of the multilevel information, information of a plurality of levels can be transferred also by the pilot signal. Here, in the present invention, “synchronized” means synchronization in a broad sense and means that the frequencies of two pilot signals are in an integer ratio relationship. By increasing / decreasing variations in the frequency difference of the pilot signal, it is possible to increase / decrease the information amount of the multi-value information to be transferred.

  An information distribution system according to the present invention is an information distribution system that transmits multi-value information from a transmission device to a reception device using a pilot signal, and the transmission device has predetermined two phases that coincide with each other in a constant cycle. A pilot signal output unit that generates pilot signals having two different fixed frequencies, and outputs a difference in the number of cycles between the pilot signals within the fixed period as an information amount of the multilevel information, and an output of the pilot signal output unit A signal transmission unit that transmits a pilot signal to the reception device, the reception device receiving a pilot signal transmitted from the signal transmission unit, and a phase of a pilot signal received by the signal reception unit A phase detector for detecting the fixed frequency for each fixed frequency, and the number of cycles within the predetermined period of the phase detected by the phase detector Counted for each fixed frequency, characterized in that it comprises an information output unit for outputting the multi-value information of information amount corresponding to the difference between the number of cycles between the fixed frequency.

  Since the difference in the number of cycles of pilot signals of two different frequencies is transmitted as the amount of information of multilevel information, information of a plurality of levels can be transferred also by the pilot signal. By increasing / decreasing variations in the difference in the number of cycles of the pilot signal, it is possible to increase / decrease the amount of multi-value information to be transferred. Since the pilot signal frequency is fixed to two types, the amount of information to be transferred can be increased without increasing the configuration of the pilot signal oscillation source.

  In the information distribution system according to the present invention, the information output unit sets the fixed period from the timing at which the phases of the pilot signals for each fixed frequency detected by the phase detection unit match to the next matching timing. Is preferred. By setting the interval at which the information output unit counts the number of cycles to an interval between timings at which the phases of the two fixed frequency pilot signals coincide with each other, the number of cycles of each pilot signal can be accurately counted.

  An information distribution method according to the present invention is an information distribution method for transmitting multilevel information using a pilot signal, and generates a plurality of predetermined synchronized pilot signals of different frequencies, and information on the multilevel information A pilot signal output procedure for selecting and outputting two pilot signals having a frequency difference according to the amount, a signal transmission procedure for transmitting a pilot signal output in the pilot signal output procedure, and a pilot transmitted in the signal transmission procedure A signal reception procedure for receiving a signal, a frequency detection procedure for detecting a frequency of a pilot signal received in the signal reception procedure, and a difference between frequencies detected in the frequency detection procedure are calculated, and an information amount corresponding to the difference is calculated. And an information output procedure for outputting the multi-value information.

  Since the frequency difference between the pilot signals of two different frequencies is transmitted as the information amount of the multilevel information, information of a plurality of levels can be transferred also by the pilot signal. Here, in the present invention, “synchronized” means synchronization in a broad sense and means that the frequencies of two pilot signals are in an integer ratio relationship. By increasing / decreasing variations in the frequency difference of the pilot signal, it is possible to increase / decrease the information amount of the multi-value information to be transferred.

  An information distribution method according to the present invention is an information distribution method for transmitting multilevel information using a pilot signal, and generates pilot signals of two different fixed frequencies whose phases match at a constant cycle, A pilot signal output procedure for outputting a difference in the number of cycles between the pilot signals within the fixed period as the information amount of the multilevel information, and a signal transmission for transmitting the pilot signal output in the pilot signal output procedure to the receiving device A procedure for receiving a pilot signal transmitted in the signal transmission procedure, a phase detection procedure for detecting the phase of the pilot signal received in the signal reception procedure for each fixed frequency, and a detection in the phase detection procedure The number of cycles within the certain period of the measured phase is counted, and information according to the difference between the fixed frequencies of the number of cycles is counted. And having a data output procedure to output the multi-value information amount, a.

  Since the difference in the number of cycles of pilot signals of two different frequencies is transmitted as the amount of information of multilevel information, information of a plurality of levels can be transferred also by the pilot signal. By increasing / decreasing variations in the difference in the number of cycles of the pilot signal, it is possible to increase / decrease the amount of multi-value information to be transferred. Since the pilot signal frequency is fixed to two types, the amount of information to be transferred can be increased without increasing the configuration of the pilot signal oscillation source.

  In the information distribution system according to the present invention, in the information output procedure, the period from the timing at which the phases of the pilot signals for each fixed frequency detected in the phase detection procedure are matched to the timing at which the pilot signals are matched next is set as the fixed period. Is preferred. By setting the interval at which the information output unit counts the number of cycles to an interval between timings at which the phases of the two fixed frequency pilot signals coincide with each other, the number of cycles of each pilot signal can be accurately counted.

  A transmission apparatus according to the present invention is a transmission apparatus used in an information distribution system that transmits multilevel information from a transmission apparatus to a reception apparatus using a pilot signal, and is a pilot signal having a plurality of predetermined synchronized different frequencies. A pilot signal output unit that selects and outputs two pilot signals having a frequency difference corresponding to the information amount of the multi-level information, and transmits the pilot signal output from the pilot signal output unit to the receiving device And a signal transmission unit.

  Since the frequency difference between the pilot signals of two different frequencies is transmitted as the information amount of the multilevel information, information of a plurality of levels can be transferred also by the pilot signal. Here, in the present invention, “synchronized” means synchronization in a broad sense and means that the frequencies of two pilot signals are in an integer ratio relationship. By increasing / decreasing variations in the frequency difference of the pilot signal, it is possible to increase / decrease the information amount of the multi-value information to be transferred.

  A transmission apparatus according to the present invention is a transmission apparatus used in an information distribution system that transmits multilevel information from a transmission apparatus to a reception apparatus using a pilot signal, and includes two predetermined phases whose phases coincide with each other at a constant period. A pilot signal output unit that generates pilot signals having different fixed frequencies, and outputs a difference in the number of cycles between the pilot signals within the fixed period as an information amount of the multilevel information, and a pilot output from the pilot signal output unit And a signal transmission unit that transmits a signal to the receiving device.

  Since the difference in the number of cycles of pilot signals of two different frequencies is transmitted as the amount of information of multilevel information, information of a plurality of levels can be transferred also by the pilot signal. By increasing / decreasing variations in the difference in the number of cycles of the pilot signal, it is possible to increase / decrease the amount of multi-value information to be transferred. Since the pilot signal frequency is fixed to two types, the amount of information to be transferred can be increased without increasing the configuration of the pilot signal oscillation source.

  A receiving apparatus according to the present invention is used in an information distribution system that transmits multilevel information from a transmitting apparatus to a receiving apparatus using a pilot signal, and generates pilot signals of a plurality of predetermined synchronized different frequencies, A receiving device that receives two pilot signals that are output by selecting two pilot signals having a frequency difference according to the information amount of multilevel information, and that receives the pilot signals transmitted by the transmitting device. A frequency detection unit that detects a frequency of a pilot signal received by the signal reception unit, and a difference between frequencies detected by the frequency detection unit, and outputs the multi-value information having an information amount corresponding to the difference And an information output unit.

  Since the frequency difference between the pilot signals of two different frequencies is received as the information amount of the multilevel information, information of a plurality of levels can be transferred also by the pilot signal. Here, in the present invention, “synchronized” means synchronization in a broad sense and means that the frequencies of two pilot signals are in an integer ratio relationship. By increasing / decreasing variations in the frequency difference of the pilot signal, it is possible to increase / decrease the information amount of the multi-value information to be transferred.

  A receiving apparatus according to the present invention is used in an information distribution system that transmits multilevel information from a transmitting apparatus to a receiving apparatus by using a pilot signal, and pilots of two different fixed frequencies that have predetermined phases that coincide with each other at a constant period. A receiving device for generating a signal and receiving a pilot signal output as an amount of information of the multi-value information, wherein a difference in the number of cycles between the pilot signals within the fixed period is received, wherein the pilot transmitted by the signal transmitting unit A signal receiving unit for receiving a signal, a phase detecting unit for detecting the phase of a pilot signal received by the signal receiving unit for each fixed frequency, and the number of cycles within the fixed period of the phase detected by the phase detecting unit For each fixed frequency, and an information output unit that outputs the multi-value information with an information amount corresponding to a difference in the number of cycles between the fixed frequencies; Characterized in that it comprises.

  Since the difference in the number of cycles of pilot signals of two different frequencies is received as the amount of information of multi-level information, information of a plurality of levels can be transferred also by the pilot signal. By increasing / decreasing variations in the difference in the number of cycles of the pilot signal, it is possible to increase / decrease the amount of multi-value information to be transferred. Since the pilot signal frequency is fixed to two types, the amount of information to be transferred can be increased without increasing the configuration of the pilot signal oscillation source.

  According to the present invention, since a frequency difference or a cycle number difference caused by a plurality of pilot signals having different predetermined frequencies is transmitted as the information amount of the multilevel information, the information distribution system capable of transferring the multilevel information by the pilot signal An information distribution method executed by the information distribution system, a transmission device and a reception device used in the information distribution system can be provided.

Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiment described below is an example of the configuration of the present invention, and the present invention is not limited to the following embodiment.
(Embodiment 1)
FIG. 1 is a configuration diagram of an information distribution system according to the first embodiment. The information distribution system shown in FIG. 1 performs the information distribution method according to the present embodiment. The information distribution system transmits multi-value information from the transmission device 1 to the reception device 14 using a pilot signal. In the present embodiment, an example is shown in which the transmission device 1 and the reception device 14 are connected by the optical transmission path 9. However, the optical transmission path 9 has an input such as a radio transmission device or an amplifier using radio waves or light. A device for transmitting the distribution signal and the pilot signal input to the terminals 15a and 15b may be provided.

  The transmission apparatus 1 includes input terminals 15a and 15b, an input terminal 17 for multilevel information, a pilot signal output unit 8 that performs a pilot signal output procedure, and synthesis units 2, 3, and 5, and signal transmission that performs a signal transmission procedure. Part 4. Distribution signals transmitted from the transmission device 1 to the reception device 14 are input to the input terminals 15a and 15b. The distribution signal is a signal that the transmission device 1 should originally transmit to the reception device 14. In this embodiment, a low frequency video signal and a high frequency video signal are illustrated as examples of the distribution signal. For example, a low frequency video signal is input to the input terminal 15a. A high frequency video signal is input to the input terminal 15b. Multi-value information is input to the input terminal 17. The multi-value information is an alarm level indicating the content of the alarm according to the information amount such as “0”, “1”, “2”, and the like. The content of the alarm is, for example, whether there is a fiber break, the degree of transmission path failure, the degree of device failure or the transmission quality, or a combination thereof. For example, when the information level is “0”, the alarm level indicates a normal state with no warning, and when the information level is “1”, there is a video signal input failure. “2” indicates that there is a transmission device failure, and “3” indicates that there is a transmission path failure.

  The pilot signal output unit 8 receives multi-value information from the input terminal 17 and outputs two pilot signals corresponding to the information amount of the multi-value information. When information such as whether there is a fiber break is input to the input terminal 17, the pilot signal output unit 8 refers to a table that associates the input information with the information amount of the multi-value information. You may convert into multi-value information. The synthesizer 2 synthesizes the low frequency video signal input from the input terminal 15 a and the low frequency pilot signal input from the pilot signal output unit 8. The synthesizer 5 synthesizes the high-frequency video signal input from the input terminal 15 b and the high-frequency pilot signal input from the pilot signal output unit 8. The synthesizer 3 synthesizes the outputs of the synthesizer 2 and the synthesizer 5 and outputs them to the signal transmitter 4. The signal transmission unit 4 transmits the pilot signal output from the pilot signal output unit 8 to the reception device 14. In the present embodiment, as an example, the example in which the signal transmission unit 4 converts the combined signal input from the combining unit 3 into an optical signal and transmits the optical signal to the optical transmission line 9 is shown.

  Here, the pilot signal output from the pilot signal output unit 8 is used to monitor or isolate a video signal input failure, a transmission device failure, or a transmission path failure. In order to facilitate fault isolation, the high frequency signal is used as a high frequency video signal, and the low frequency signal is used as a low frequency video signal. Therefore, normally, it is preferable to synthesize each pilot signal with each video signal by the configuration shown in FIG. However, since each video signal and each pilot signal need only be added, the configuration of FIG. 1 is not necessarily required. For example, instead of the three combiners shown in FIG. A configuration using only two synthesizers may be used.

  The pilot signal output unit 8 generates a plurality of predetermined synchronized pilot signals of different frequencies, and selects and outputs two pilot signals having a frequency difference according to the information amount of the multilevel information. Here, the synchronization in the present embodiment refers to synchronization in a broad sense and means that the frequencies of the two pilot signals are in an integer ratio relationship. Since the two pilot signals are synchronized, the receiving apparatus 14 can calculate the frequency difference between the pilot signals and demodulate the multilevel information corresponding to the frequency difference. The variation of the frequency difference generated by the pilot signal output unit 8 is not less than the maximum value of the information amount of the multi-value information. For example, when the amount of multi-value information is 0 to 3, the number of frequency difference variations is four or more. For this reason, it is preferable that the pilot signal output unit 8 includes an oscillation reduction of the pilot signal equal to or greater than the maximum value of the information amount of the multi-value information. If the variation of the frequency difference of the pilot signal generated by the pilot signal generator is increased or decreased, the amount of information can be increased or decreased according to the variation of the frequency difference of the pilot signal.

  The reception device 14 is input from a signal reception unit 10 that performs a signal reception procedure, a frequency detection unit 11 that performs a frequency detection procedure, an information output unit 13 that performs an information output procedure, and input terminals 15 a and 15 b of the transmission device 1. An output terminal 16 for outputting the information and an output terminal 18 for multi-value information. In the receiving device 14, the signal receiving unit 10 receives the composite signal transmitted from the transmitting device 1, outputs the low frequency video signal and the high frequency video signal to the output terminal 16, and outputs the multilevel information from the output terminal 18. To do.

  The signal receiver 10 receives the pilot signal transmitted from the signal transmitter 4. For example, the signal receiving unit 10 photoelectrically converts the optical signal input from the optical transmission path 9, and the low frequency pilot signal and the high frequency pilot signal together with the low frequency video signal and the high frequency video signal included in the composite signal. Receive. The frequency detector 11 detects the frequency of the pilot signal received by the signal receiver 10. For example, the combined signal obtained by photoelectric conversion of the signal receiving unit 10 is input to the low frequency signal detecting unit 11a, the low frequency pilot signal is extracted to detect the frequency of the low frequency pilot signal, and the combined signal obtained by photoelectric conversion of the signal receiving unit 10 A signal is input to the high frequency signal detector 11b to extract the high frequency pilot signal and detect the frequency of the high frequency pilot signal. The low-frequency signal detection unit 11a includes, for example, a band-pass filter that transmits each frequency on the low-frequency side of the frequency difference generated by the pilot signal output unit 8, and detects the frequency based on whether or not the band-pass filter transmits. The high frequency signal detection unit 11b includes, for example, a band pass filter that transmits each frequency on the high frequency side of the frequency difference generated by the pilot signal output unit 8, and detects the frequency based on whether or not the band pass filter is transmitted.

The information output unit 13 calculates the difference between the frequencies detected by the frequency detection unit 11 and outputs multi-value information having an information amount corresponding to the difference to the output terminal 18. For example, the difference in frequency is calculated by calculating the difference between the frequency of the low-frequency pilot signal detected by the low-frequency signal detector 11a and the frequency of the high-frequency pilot signal detected by the high-frequency signal detector 11b. Then, the information output unit 13 determines which value of the information amount the difference corresponds to. For example, if the frequency difference is Δf ₁ , the information amount is determined as “1”, and if the frequency difference is Δf ₂ , the information amount is determined as “2”. Here, the information output unit 13 may output the information amount as it is to the output terminal 18, but it is preferable to output the contents of the alarm level that means the multi-value information. For example, if the information amount is 1, the information output unit 13 outputs a video signal input failure alarm, if the information amount is 2, outputs a transmission device failure alarm, and if the information amount is 3, the transmission line Output a failure alarm. As described above, since the frequency difference of the pilot signal is used as the information amount of the multi-level information, information of a plurality of levels can be transferred by the pilot signal.

  FIG. 2 is a frequency spectrum showing an example of a composite signal received by the signal receiving unit. FIG. 2A shows an information amount of multilevel information “0”, and FIG. 2B shows an information amount of multilevel information “1”. , (C) shows a case where the information amount of the multi-value information is “2”. For example, FIG. 2A shows a case where the information amount is “0” and there is no alarm. A low frequency pilot signal 62 and a high frequency pilot signal 63 are combined with the low frequency video signal 60 and the high frequency video signal 61. At this time, the frequency difference between the low frequency pilot signal 62 and the high frequency pilot signal 63 is Δf. When the frequency difference is Δf, the information output unit 13 does not output multi-value information, for example.

FIG. 2B shows a case where the alarm level at which the information amount is “1” is 1. A low frequency pilot signal 62 and a high frequency pilot signal 64 are combined with the low frequency video signal 60 and the high frequency video signal 61. In the state where the alarm level 1 is generated, the high frequency pilot signal 63 shown in FIG. 2A is changed to the high frequency pilot signal 64 on the plus side, and the frequency difference between the low frequency pilot signal 62 and the high frequency pilot signal 64 is changed. Is changed to Δf ₁ . When the frequency difference is Δf ₁ , the information output unit 13 outputs, for example, an alarm level “1”. Alternatively, an alarm indicating that there was a video signal input failure is output.

FIG. 2C shows a case where the alarm level at which the information amount is “2” is 2. A low frequency pilot signal 62 and a high frequency pilot signal 65 are combined with the low frequency video signal 60 and the high frequency video signal 61. In the state where the alarm level 2 is generated, the high frequency pilot signal 63 shown in FIG. 2A is changed to the negative high frequency pilot signal 65, and the frequency difference between the low frequency pilot signal 62 and the high frequency pilot signal 65 is changed. Is changed to Δf ₂ . When the frequency difference is Δf ₂ , the information output unit 13 outputs, for example, an alarm level “2”. Alternatively, an alarm indicating that there is a transmitter failure is output. As described above, since the transmission device transmits a pilot signal having a frequency difference corresponding to the multi-value information, multi-value information corresponding to the frequency difference, an alarm level, or an alarm corresponding to the alarm level can be output. Further, by providing three or more frequency deviation amounts, three or more alarm levels can be transferred from the transmission device to the reception device.

  In the information distribution system shown in FIG. 1, the amplitude of the pilot signal output from the pilot signal output unit 8 is used for fault monitoring and isolation, which are the original purposes of the pilot signal. Also, the frequency of the pilot signal output from the pilot signal output unit 8 varies due to variations and modulation of the pilot signal itself, frequency variations of the local oscillator during demodulation, and the like. On the other hand, if the pilot signal output from the pilot signal output unit 8 is two pilot signals obtained by dividing the pilot signal from the same oscillation source, even if there is modulation of the pilot signal itself or frequency fluctuation of the local oscillator during demodulation, The frequency difference can be kept constant. For this reason, it is preferable that the pilot signal output unit 8 outputs two pilot signals obtained by frequency division from the same transmission source. The difference frequency between the two pilot signals divided from the same oscillator can be effectively used for information transmission. For example, a signal generation unit 7 that generates pilot signals of three or more different frequencies that are synchronized with each other, and two pilots of low frequency and high frequency that have a frequency difference corresponding to the information amount of multilevel information It is preferable to include a selection unit 6 that selects a signal.

  FIG. 3 is a pickup diagram showing a first form of the pilot signal output unit. The pilot signal output unit 8 includes n signal generation units 20, 21, and 22 that generate predetermined synchronized n different frequency difference pilot signal pairs, and n signal generation units 20, 21, A selection unit 23 that selects and outputs two pilot signal pairs having a frequency difference corresponding to the information amount of the multi-level information from the n pairs of pilot signals having different frequency differences generated by 22 . The selection unit 23 outputs the low frequency pilot signal to the synthesis unit 2 and outputs the high frequency pilot signal to the synthesis unit 5. In FIG. 3, for simplicity, the n signal generators 20, 21, and 22 are omitted except for the first signal generator 20, the second signal generator 21, and the nth signal generator 22. .

The signal generators 20, 21, and 22 generate a synchronized low frequency pilot signal and high frequency pilot signal, respectively. Signal generator 20 generates a high-frequency pilot signal of the low-frequency pilot signal and the frequency f ₁₂ of the frequency f _11. The signal generator 22 generates a low frequency pilot signal having a frequency f _{n1 and} a high frequency pilot signal having a frequency f _n2 . As described above, the i-th (i = 1 to n) signal generation unit generates the low-frequency pilot signal having the frequency f _{i1 and} the high-frequency pilot signal having the frequency f _i2 . In this case, the frequencies of the signal generators 20, 21, and 22 satisfy Equation 1 with i ≠ j.

For example, when the multi-level information of the alarm level “m” is input from the input terminal 17, the selection unit 23 receives the low-frequency pilot signal having the frequency f _i1 and the frequency f _i2 input from the signal generation units 20, 21, and 22. The m-th frequency (f _m1 , f _m2 ) is selected from n pairs with the high frequency pilot signal of, and a low frequency pilot signal of frequency f _{m1 and} a high frequency pilot signal of frequency f _m2 are output. .

Here, the low-frequency pilot signal and the high-frequency pilot signal generate a frequency within the range if there is a limit on the frequency shift. For example, if the frequency of the low frequency pilot signal is 100 MHz and the limit of frequency deviation is ± 20 ppm, the frequencies f _{12 to} f _n2 of the high frequency pilot signal are in the range of 99998 kHz to 100002 kHz.

  FIG. 4 is a pickup diagram showing a second form of the pilot signal output unit. The pilot signal output unit 8 generates a low frequency pilot signal generating unit 30 that generates a predetermined low frequency pilot signal having a fixed frequency, and generates n different high frequency pilot signals that are synchronized with the low frequency pilot signal. Of the high frequency pilot signals generated by the high frequency pilot signal generators 31, 32, 33 and the high frequency pilot signal generators 31, 32, 33, the frequency corresponding to the multilevel information input from the input terminal 17 And a selector 34 that selects and outputs a high-frequency pilot signal that is the difference. In FIG. 4, for the sake of simplicity, the n high frequency pilot signal generators 31, 32, 33 are the first high frequency pilot signal generator 31, the second high frequency pilot signal generator 32, the n th Omitted except for the high frequency pilot signal generator 33. The low frequency pilot signal generator 30 outputs the low frequency pilot signal to the synthesizer 2. The selector 34 outputs the high frequency pilot signal to the synthesizer 5.

A low frequency reference signal for synchronizing with the low frequency pilot signal is input from the low frequency pilot signal generator 30 to each of the n high frequency pilot signal generators 31, 32, 33. The frequencies f _{12 to} f _n2 of the high frequency pilot signals generated by the n high frequency pilot signal generators are different from each other. The selection unit 34 has a frequency at which the frequency difference with the frequency f ₁ of the low-frequency pilot signal generated by the low-frequency pilot signal generation unit 30 becomes a numerical value corresponding to the information amount of the multilevel information input from the input terminal 17. The high frequency pilot signal is selected and output. For example, if the alarm level of the multi-value information input to the selection unit 34 is “m”, the selection unit 34 selects and outputs a high-frequency pilot signal having a frequency _fm2 . When the frequency shift is limited, it is preferable that the high frequency pilot signal generators 31, 32, and 33 generate frequencies within the range. By setting the generation of the low frequency pilot signal to a fixed frequency, the low frequency pilot signal generation unit 30 can be shared and the cost of the circuit can be reduced.

(Embodiment 2)
An information distribution system according to Embodiment 2 will be described with reference to FIG. The information distribution system according to the present embodiment performs an information distribution method, and transmits multi-value information from the transmission device 1 to the reception device 14 using a pilot signal. The transmission apparatus 1 includes distribution signal input terminals 15a and 15b, multi-value information input terminal 17, a pilot signal output unit 8 for performing a pilot signal output procedure, combining units 2, 3, and 5, and a signal transmission procedure. And a signal transmission unit 4 to be performed. The reception device 14 includes a signal reception unit 10 that performs a signal reception procedure, a phase detection unit 11 that performs a phase detection procedure, and an information output unit 13 that performs an information output procedure.

  The information distribution system according to the present embodiment is different from the first embodiment in the following points. First, in the transmission apparatus 1, the function of the pilot signal output unit 8 that performs the pilot signal output procedure is different. Further, the receiving device 14 is different in that the frequency detection unit 11 that performs the frequency detection procedure is the phase detection unit 11 that performs the phase detection procedure. Moreover, the function of the information output part 13 which performs an information output procedure differs. Hereinafter, different points will be described.

  The pilot signal output unit 8 generates pilot signals of two different fixed frequencies whose phases coincide with each other at a constant period, and uses the difference in the number of cycles between the pilot signals within the constant period as the information amount of the multilevel information. Output. Only two pilot signals are generated by the pilot signal output unit 8. For example, there are a low-frequency pilot signal and a high-frequency pilot signal having different frequencies, and it is not necessary to change these frequencies as in the first embodiment. However, in the present embodiment, it is necessary that the phases of the low-frequency pilot signal and the high-frequency pilot signal coincide with each other at a constant period. The pilot signal output unit 8 thins out the cycle of the pilot signal in accordance with the amount of multi-value information input from the input terminal 17 and changes the number of cycles. The cycle to be thinned out may be any cycle other than the cycle having the same phase. For example, if the thinning cycle is a low frequency pilot signal or a high frequency pilot signal, the configuration of the pilot signal output unit 8 is simplified. If the thinning cycle is both a low-frequency pilot signal and a high-frequency pilot signal, variations in the number of thinning cycles increase, so that the amount of multilevel information can be increased. Furthermore, the fixed period is not limited to the minimum period in which the phases coincide with each other, and may be any integer multiple of the minimum period.

  FIG. 5 is a pickup diagram of a pilot signal output unit according to the second embodiment. The pilot signal output unit 8 thins out the number of cycles corresponding to the information amount of the multilevel information input from the input terminal 17 and the low frequency pilot signal generation unit 30 that generates a low frequency pilot signal of a predetermined fixed frequency. And a high frequency pilot signal generator 41 for outputting a high frequency pilot signal. The high frequency pilot signal generator 41 generates a high frequency pilot signal source 42 that generates a high frequency pilot signal having a fixed frequency different from that of the low frequency pilot signal, and a high frequency pilot signal generated by the high frequency pilot signal source 42. And a selection unit 43 that thins out and outputs a number of cycles corresponding to the amount of value information. For example, the selection unit 43 performs amplitude modulation on the high frequency pilot signal input from the high frequency pilot signal source 42 according to the information amount of the multilevel information, and thins out the number of cycles. For example, if the amount of information is “m”, m cycles are thinned out from n cycles (where n ≧ m) within the fixed period with the same phase. The selection unit 43 may pulse the high frequency pilot signal to perform pulse amplitude modulation.

  The high frequency pilot signal source 42 receives the low frequency reference signal from the low frequency pilot signal generator 30 and matches the phase of the high frequency pilot signal generated by the high frequency pilot signal source 42 with the low frequency pilot signal at a constant period. . The low frequency reference signal is, for example, a signal having the same frequency and the same phase as the low frequency pilot signal. The signal generation source for causing the phases of the low frequency pilot signal and the high frequency pilot signal to coincide with each other at a constant period is not limited to the low frequency pilot signal generation unit 30 shown in FIG. 5 and may be provided independently.

  FIG. 6 is an example of a time waveform of a pilot signal output from the pilot signal output unit, where (a) is a low-frequency pilot signal, (b) is a high-frequency pilot signal when the amount of information is “0”, and (c ) Shows a high frequency pilot signal when the information amount is “1”, and (d) shows a high frequency pilot signal when the information amount is “2”. The phase of the low-frequency pilot signal 71 shown in FIG. 6A and the high-frequency pilot signals 72, 73, and 74 shown in FIGS. 6A to 6D show an example in which the phase matching timing is the rising timing of the sine wave, it may be the falling timing of the sine wave. 6A to 6D show an example in which the pilot signal is a sine wave, it may be a pulse wave. In the case of a pulse wave, if the number of pulses is used instead of the number of cycles, the same effect as that of the present embodiment can be obtained.

The total number of cycles of the low frequency pilot signal 71 existing within the constant period T of the low frequency pilot signal 71 shown in FIG. 6A is S ₁ , and the low frequency pilot signal 72 shown in FIG. 6B is constant. present in the period T, the total number of cycles of the high frequency pilot signal 72 is assumed to be S _2. In this case, when the multi-value information indicating that the alarm level is “1” is input, the selection unit thins out one cycle to be thinned out from the high frequency pilot signal 72, and calculates the number of cycles existing within the fixed period T as ( and it outputs the high frequency pilot signal 73 shown in FIG. 6 (c) that the S ₂ -1). Further, when the multi-value information indicating that the alarm level is “2” is input, the selection unit thins out two cycles to be thinned out from the high frequency pilot signal 72, and calculates the number of cycles existing within the fixed period T (S _The high frequency pilot signal 74 shown in FIG. In this way, by changing the number of cycles of the high-frequency pilot signal 72, the high-frequency pilot signal can be assigned to multi-value information such as an alarm level in accordance with the alarm level. In the present embodiment, multi-value information can be assigned even if there is only one signal source for the high frequency pilot signal, so that the configuration of the signal generator for the high frequency pilot signal can be simplified, and the circuit cost can be reduced. Can be reduced.

  The phase detector 11 shown in FIG. 1 detects the phase of the pilot signal received by the signal receiver 10 for each fixed frequency. The fixed frequency is the frequency of the low frequency pilot signal and the frequency of the high frequency pilot signal. That is, two different fixed frequencies generated by the pilot signal output unit 8. In the present embodiment, since the frequency is fixed at two different fixed frequencies, two means for extracting frequency components are sufficient. For example, the low frequency signal detection unit 11 a extracts the frequency component of the low frequency pilot signal by extracting the fixed frequency component on the low frequency side from the combined signal obtained by photoelectric conversion of the signal receiving unit 10. And the low frequency signal detection part 11a detects the phase of the frequency component of a low frequency pilot signal. On the other hand, the high frequency signal detection unit 11b extracts the frequency component of the high frequency pilot signal by extracting the fixed frequency component on the high frequency side from the combined signal obtained by photoelectric conversion of the signal receiving unit 10. And the high frequency signal detection part 11b detects the phase of the frequency component of a high frequency pilot signal. Here, the low frequency signal detection units 11a and 11b can be configured by, for example, a band pass filter that extracts a frequency component and a phase detection circuit that detects the phase of the frequency component that has passed through the band pass filter. The phase detection circuit may detect the phase of the pulsed low frequency pilot signal and output the pulse signal to the information output unit 13. The same applies to the high frequency pilot signal.

The information output unit 13 counts the number of cycles within a fixed period of the phase detected by the phase detection unit 11 for each fixed frequency, and outputs multi-value information with an information amount corresponding to the difference in the number of cycles between the fixed frequencies. . For example, the information output unit 13 determines the number of cycles of the low frequency pilot signal from the phase of the low frequency pilot signal input from the low frequency signal detection unit 11a, and the phase of the two pilot signals generated by the pilot signal output unit 8 Count over the constant period of coincidence. On the other hand, the information output unit 13 uses the phase of the two pilot signals generated by the pilot signal output unit 8 to generate the number of cycles of the high frequency pilot signal from the phase of the high frequency pilot signal input from the high frequency signal detection unit 11b. Are counted over the fixed period. Then, the information output unit 13 calculates a difference between the number of cycles of the low frequency pilot signal and the number of cycles of the high frequency pilot signal. Then, the information output unit 13 determines which value of the information amount the difference corresponds to. For example, if the number of cycles of the high frequency pilot signal (S ₂ -2) is different from the number of cycles S ₁ of the low frequency pilot signal, the difference in the number of cycles of both pilot signals is (S ₁ -S ₂ -2) Therefore, it is two less than the difference (S ₁ −S ₂ ) in the number of cycles of both pilot signals in the normal case where there is no decimation. At this time, the information output unit 13 determines that the amount of information is “2” and outputs it to the output terminal 18. Here, the information output unit 13 may output the information amount as it is to the output terminal 18 as in the first embodiment, but it is preferable to output the contents of the alarm level that the multi-value information means. Thus, since the difference in the number of cycles between pilot signals within a certain period is used as the information amount of the multi-value information, information of a plurality of levels can be transferred by the pilot signal. The amount of information can be increased or decreased in accordance with variations in the difference in the number of pilot signal cycles generated by the pilot signal generator.

  Here, in the information distribution system according to the present embodiment, the information output unit 13 sets a fixed period from the timing at which the phases of the pilot signals for each fixed frequency detected by the phase detection unit 11 match to the next matching timing. It is preferable to do. In other words, in the information output procedure, it is preferable that the period from the timing at which the phases of the pilot signals for each fixed frequency detected in the phase detection procedure match to the timing at which they match next is set to a constant period. For example, it is preferable to provide means for detecting the timing at which the phases of the low frequency pilot signal and the high frequency pilot signal coincide with each other before counting the number of cycles of the low frequency pilot signal and the high frequency pilot signal. In this case, the number of cycles of the low frequency pilot signal and the high frequency pilot signal is counted over a certain period from the phase next to the phase in which the phases of the low frequency pilot signal and the high frequency pilot signal match. In addition, before the counting of the number of cycles of the low-frequency pilot signal and the high-frequency pilot signal, the timing at which the phase coincides next from the timing at which the phases of the low-frequency pilot signal and the high-frequency pilot signal coincide with each other is detected. There may be provided means for outputting only. By detecting the coincidence of the phases of the pilot signals, the number of cycles can be accurately counted.

  The present invention can be used in an information transmission system that transmits sub-multilevel information while transmitting a plurality of pieces of main information.

1 is a configuration diagram of an information distribution system according to Embodiment 1. FIG. FIG. 6 is a frequency spectrum showing an example of a composite signal received by the signal receiving unit, where (a) shows the information amount of multi-value information “0”, (b) shows the information amount of multi-value information “1”, and (c). Indicates a case where the amount of multi-value information is “2”. It is a pick-up figure which shows the 1st form of a pilot signal output part. It is a pick-up figure which shows the 2nd form of a pilot signal output part. 6 is a pickup diagram of a pilot signal output unit according to Embodiment 2. FIG. FIG. 6 is an example of a time waveform of a pilot signal output from a pilot signal output unit, where (a) is a pilot signal on the low frequency side, (b) is a pilot signal on the high frequency side when the amount of information is “0”, (c ) Indicates a pilot signal on the high frequency side when the information amount is “1”, and (d) indicates a pilot signal on the high frequency side when the information amount is “2”.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmitter 2, 3, 5 Synthesizer 4 Signal transmission part 6 Selection part 7 Pilot signal generation part 8 Pilot signal output part 9 Optical transmission line 10 Signal receiving part 11 Frequency detection part 11a Low frequency signal detection part 11b High frequency signal detection Unit 13 Notification Information Output Unit 14 Receiver 15a Low Frequency Signal Input Terminal 15b High Frequency Signal Input Terminal 16 Video Information Output Terminal 17 Multilevel Information Input Terminal 18 Multilevel Information Output Terminal 20, 21, 22 Signal Generator 23 Selection unit 30 Low frequency pilot signal generation unit 31, 32, 33 High frequency pilot signal generation unit 34 Selection unit 41, 42 High frequency pilot signal generation unit 43 Selection unit 60 Low frequency video signal 61 High frequency video signal 62 Low frequency pilot signal 63, 64, 65 High frequency pilot signal 71 Low frequency pilot Fixed period of phase matching issue 72, 73, 74 high-frequency pilot signal T embodiments pilot signals of two low-frequency side and the high-frequency pilot signal

Claims (10)

An information distribution system for transmitting multilevel information from a transmission device to a reception device using a pilot signal,
The transmitter is
A pilot signal output unit for generating a plurality of predetermined synchronized pilot signals of different frequencies, and selecting and outputting two pilot signals having a frequency difference according to the amount of information of the multilevel information;
A signal transmission unit for transmitting the pilot signal output from the pilot signal output unit to the reception device,
The receiving device is:
A signal receiver for receiving a pilot signal transmitted by the signal transmitter;
A frequency detector for detecting a frequency of a pilot signal received by the signal receiver;
An information distribution system comprising: an information output unit that calculates a difference between frequencies detected by the frequency detection unit and outputs the multi-value information having an information amount corresponding to the difference. An information distribution system for transmitting multilevel information from a transmission device to a reception device using a pilot signal,
The transmitter is
A pilot signal that generates two different fixed-frequency pilot signals having phases that coincide with each other at a fixed period and outputs a difference in the number of cycles between the pilot signals within the fixed period as an information amount of the multilevel information An output section;
A signal transmission unit for transmitting the pilot signal output from the pilot signal output unit to the reception device,
The receiving device is:
A signal receiver for receiving a pilot signal transmitted by the signal transmitter;
A phase detector that detects the phase of a pilot signal received by the signal receiver for each fixed frequency;
An information output that counts the number of cycles within the fixed period of the phase detected by the phase detector for each fixed frequency and outputs the multi-value information with an information amount corresponding to the difference in the number of cycles between the fixed frequencies An information distribution system comprising: a section.   3. The information output unit according to claim 2, wherein the period from the timing at which the phases of the pilot signals for each fixed frequency detected by the phase detection unit coincide with each other to the next coincidence is set as the fixed period. Information distribution system. An information distribution method for transmitting multilevel information using a pilot signal,
A pilot signal output procedure for generating a plurality of predetermined synchronized pilot signals of different frequencies, and selecting and outputting two pilot signals having a frequency difference according to the information amount of the multilevel information;
A signal transmission procedure for transmitting the pilot signal output in the pilot signal output procedure;
A signal reception procedure for receiving a pilot signal transmitted in the signal transmission procedure;
A frequency detection procedure for detecting the frequency of the pilot signal received in the signal reception procedure;
An information distribution method comprising: an information output procedure for calculating a difference between frequencies detected by the frequency detection procedure and outputting the multi-value information having an information amount corresponding to the difference. An information distribution method for transmitting multilevel information using a pilot signal,
A pilot signal that generates two different fixed-frequency pilot signals having phases that coincide with each other at a fixed period and outputs a difference in the number of cycles between the pilot signals within the fixed period as an information amount of the multilevel information Output procedure and
A signal transmission procedure for transmitting the pilot signal output in the pilot signal output procedure to the receiver;
A signal reception procedure for receiving a pilot signal transmitted in the signal transmission procedure;
A phase detection procedure for detecting the phase of the pilot signal received in the signal reception procedure for each fixed frequency;
An information output procedure for counting the number of cycles within the fixed period of the phase detected by the phase detection procedure, and outputting the multi-value information having an information amount corresponding to a difference between the fixed frequencies of the number of cycles. An information distribution method comprising:   6. The information output procedure according to claim 5, wherein the fixed period is from a timing at which phases of pilot signals for each fixed frequency detected in the phase detection procedure match to a timing at which they match next. Information delivery method. A transmission device used in an information distribution system for transmitting multilevel information from a transmission device to a reception device using a pilot signal,
A pilot signal output unit for generating a plurality of predetermined synchronized pilot signals of different frequencies, and selecting and outputting two pilot signals having a frequency difference according to the amount of information of the multilevel information;
And a signal transmission unit configured to transmit the pilot signal output from the pilot signal output unit to the reception device. A transmission device used in an information distribution system for transmitting multilevel information from a transmission device to a reception device using a pilot signal,
A pilot signal that generates two different fixed-frequency pilot signals having phases that coincide with each other at a fixed period and outputs a difference in the number of cycles between the pilot signals within the fixed period as an information amount of the multilevel information An output section;
And a signal transmission unit configured to transmit the pilot signal output from the pilot signal output unit to the reception device. Used in an information distribution system that transmits multilevel information from a transmission device to a reception device using a pilot signal, and generates a plurality of predetermined synchronized pilot signals of different frequencies, according to the amount of information of the multilevel information A receiving apparatus for receiving two pilot signals output by selecting two pilot signals having different frequency differences,
A signal receiver for receiving a pilot signal transmitted by the transmitter;
A frequency detector for detecting a frequency of a pilot signal received by the signal receiver;
An information output unit, comprising: an information output unit that calculates a difference between frequencies detected by the frequency detection unit and outputs the multi-value information having an information amount corresponding to the difference. A pilot signal is used in an information distribution system for transmitting multilevel information from a transmission device to a reception device, and pilot signals of two different fixed frequencies whose phases coincide with each other at a constant cycle are generated. Receiving a pilot signal that is output as the amount of information of the multi-value information, the difference in the number of cycles between the pilot signals in
A signal receiver for receiving a pilot signal transmitted by the signal transmitter;
A phase detector that detects the phase of a pilot signal received by the signal receiver for each fixed frequency;
An information output that counts the number of cycles within the fixed period of the phase detected by the phase detector for each fixed frequency and outputs the multi-value information with an information amount corresponding to the difference in the number of cycles between the fixed frequencies A receiving device.

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