Transponder unit, transponder unit control apparatus, transponder unit control method and recording medium recording transponder unit control program

A transponder includes a CDR section that extracts clocks from an input signal, an oscillating section that can output various frequencies to the CDR section, a frequency instruction processing section that instructs the oscillating section to output an arbitrary frequency, a detection processing section, and a frame processing section control section. The detection processing section determines whether the frequency output from the oscillating section and an input signal synchronize in frequency or not in response to an instruction by the frequency instruction processing section, and detects a synchronization frequency. The frame processing section control section operates a frame processing section based on the synchronization frequency detected by the detection processing section.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments herein relate to a transponder unit, a transponder unit control apparatus, a transponder unit control method and a recording medium recording a transponder unit control program.

2. Description of the Related Art

WDM (Wavelength Division Multiplexing) is used commonly in the optical communication network field to increase the transmission capability of an optical fiber line. A WDM system applies the characteristic that optical signals with different wavelengths do not interfere with each other. A WDM system transmits multiple optical signals with different wavelengths through a number of transponder units equal to the number of wavelengths to be multiplexed.

A wide variety of client data protocols has appeared in recent years for use in optical communication in the WDM system. The client data protocols mainly use transponders applicable to various data protocol rather than a transponder only applicable to a specific data protocol. For example, SONET/SDH was predominate in existing systems while transponders which are compliant with data-related data protocols such as Giga Bit Ethernet (registered trademark) (GbE) or video-related data protocols such as DV6000 have become predominate.

Here, in a conventional WDM system, all transponders (such as a transponder unit A, a transponder unit B and a transponder unit C inFIG. 11) must define data protocols to be supported (or used). The definition is mainly performed manually (refer to (1) and (2) inFIG. 11).

JP-A-2004-64585, for example, discloses a technology including, in SDH line terminal equipment, identifying a line type of a received frame and processing the received frame by using setting data corresponding to the identified line type. More specifically, the SDH line terminal equipment stores setting data corresponding to the line type of the SDH line. Then, upon reception of a frame, the format of the received frame is identified, and the line type is thus identified. Then, the received frame is processed based on the setting data corresponding to the identified line type.

SUMMARY OF THE INVENTION

According to an aspect of an embodiment, a transponder unit comprises:

a CDR (Clock Data Recovery) section that extracts clocks from an input signal, and an oscillating section that can output various frequencies to the CDR section;

a frequency instruction processing section that instructs the oscillating section to output an arbitrary frequency;

a detection processing section that determines whether the frequency output from the oscillating section and an input signal synchronize in frequency or not in response to an instruction by the frequency instruction processing section, and detects a synchronization frequency; and

a frame processing section control section that operates a frame processing section based on the synchronization frequency detected by the detection processing section.

According to still another aspect of an embodiment, a transponder unit control apparatus comprises:

a transponder unit having a CDR section that extracts clocks from an input signal, and an oscillating section that can output various frequencies to the CDR section, a frequency instruction processing section that instructs the oscillating section to output an arbitrary frequency, a detection processing section that determines whether the frequency output from the oscillating section and an input signal synchronize in frequency or not in response to an instruction by the frequency instruction processing section, and detects a synchronization frequency, and a frame processing section control section that operates a frame processing section based on the synchronization frequency detected by the detection processing section; and

a control section that controls the transponder unit.

According to still another aspect of an embodiment, a transponder unit control method comprises:

extracting clocks from an input signal;

outputting an arbitrary frequency;

determining whether the frequency and the input signal synchronize in frequency or not and detecting a synchronization frequency; and

processing a frame section on the synchronization frequency.

According to still another aspect of an embodiment, a recording medium recording a transponder unit control program causes a computer to perform:

causing a CDR section to extract clocks from an input signal;

instructing to an oscillating section output an arbitrary frequency from;

determining whether the frequency output from the oscillating section and the input signal synchronize in frequency or not in response to the instruction, and detecting a synchronization frequency; and

operating a frame processing section based on the synchronization frequency detected by the detection.

The above-described embodiments of the present invention are intended as examples, and all embodiments of the present invention are not limited to including the features described above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of a transponder unit, a transponder unit control apparatus, a transponder unit control method and a transponder unit control program according to the invention will be described in detail below with reference to attached drawings. The outline and features of a transponder unit according to embodiments and configurations and processing flows of the transponder unit will be sequentially described below.

First Embodiment

Outline and Features of Transponder Unit

First of all, the outline and features of a transponder unit according to this embodiment will be described with reference toFIG. 1.FIG. 1is a diagram showing the outline and features of a transponder unit according to this embodiment.

As shown inFIG. 1, a transponder unit according to a first embodiment includes an oscillating section that can output various frequencies (bit rates) to a CDR (Clock Data Recovery) section. The CDR section extracts clocks from an input signal and a frame processing section performs frame processing on the input signal. More specifically, the transponder unit includes an optical/electrical (O/E) converter that receives and electrically converts an optical signal from a client and an electrical/optical (E/O) converter that converts the electrically converted signal to an optical signal. The transponder unit also includes, a CDR & DRV section that extracts clocks from input data, and a frame processing section. An oscillating section that inputs a set frequency to the CDR & DRV section. Finally, a control chip controls functions of the transponder unit.

The frame processing section in the transponder unit according to the first embodiment has a processing section that is compliant with a data protocol. The frame processing section has, as shown inFIG. 1, a “SONET-related monitor section” that is a processing section compliant with a SONET-related data protocol, a “data-related monitor section” that is a processing section compliant with a data-related data protocol (such as a data protocol as in Gigabit Ethernet (registered trademark) and a “video-related monitor section” that is a processing section compliant with a video-related data protocol (such as a data protocol as in DV6000). These monitor sections operate based on the unique data protocols, and correspondence is established between each the data protocols and unique frequencies.

Then, a transponder unit as outlined above is mainly characterized in that the manual work for defining a data protocol to be used by a client can be reduced as described below.

That is, the transponder unit according to the first embodiment instructs the oscillating section to output an arbitrary frequency (bit rate) when a signal with unknown data protocol is input from a client. More specifically, the transponder unit instructs the oscillating section to sequentially output all frequencies (bit rates) that the oscillating section can output for the input signal.

Then, the transponder unit according to the first embodiment determines whether the frequencies output from the oscillating section in response to the instruction and the input signal synchronize in frequency or not and detects a synchronization frequency. The synchronization frequency is the frequency for the synchronization (refer to (1) inFIG. 1). In other words, the transponder unit determines whether all frequencies sequentially output from the oscillating section in response to the instruction and the input signal synchronize (LOCK) in frequency or not and detects the frequency band for the synchronization (LOCK). Then, the transponder unit detects the center frequency in the frequency band for the synchronization (LOCK) as the synchronization frequency.

Then, the transponder unit according to the first embodiment operates the frame processing section based on the detected synchronization frequency. For example, as described in (2) inFIG. 1, the transponder unit instructs the control chip to operate the frame processing section and the CDR & DRV section based on the detected frequency. As a result, the frame processing section and CDR & DRV section process an input signal based on the set frequency, as described in (3) inFIG. 1. In particular, the frame processing section has a processing section (monitor section) that operates based on a unique data protocol (for example, the monitor section may be the SONET-related monitor section, the data-related monitor section or the video-related monitor section). The frame processing section operates the processing section (monitor section) based on the data protocol corresponding to an instructed frequency to perform frame processing.

Thus, as described in the main characteristic, the transponder unit according to the first embodiment can reduce the manual work for defining a data protocol to be used by a client.

Configuration of Transponder Unit

Next, with reference toFIG. 2, a configuration of the transponder unit shown inFIG. 1will be described.FIG. 2is a block diagram showing a configuration of the transponder unit. As shown inFIG. 2, a transponder unit1includes a client side input/output section10, a client side CDR & DRV section20, a client side oscillating section30, a frame processing section40, a network side CDR & DRV section50, a network side oscillating section60, a network side input/output section70and a control section100. Notably, the configuration of the transponder unit according to this embodiment will be described mainly on the points pertaining to this embodiment. The description on other configuration will be omitted or will be brief since it is the same as the one in a conventional transponder unit.

The client side input/output section10has a client side O/E section11that receives and electrically converts an optical signal from a client and a client side E/O section12that optically converts an electric signal and outputs the result to a client.

The client side CDR & DRV section20has a client side CDR (Clock Data Recovery) section21that extracts clocks from an input signal and a DRV (drive) section22that performs the inverse processing.

The client side oscillating section30is an oscillating section that outputs various frequencies to the client side CDR section21. More specifically, the client side oscillating section30outputs the frequency instructed to a frequency setting section102by a frequency instructing section108, which will be described later, to the client side CDR section21.

The network side CDR & DRV section50has the same function as that of the client side CDR & DRV section20. The network side oscillating section60has the same function as that of the client side oscillating section30. The network side input/output section70has the same function as that of the client side input/output section10.

The frame processing section40performs frame processing on an input signal. More specifically, the frame processing section40performs processing of adding control information, for example, to an input signal and constructing a frame structure (which will be called frame addition processing) under the control of the frame processing control section110, which will be described later. Alternatively, the frame processing section40performs processing of removing a frame from an input signal (which will be called frame removal processing). In particular, the frame processing section40performs frame processing based on the settings in a speed & frequency setting data section106, which will be described later, controlled by the frame processing control section110and a frame processing setting data section107(or by using a monitor section compliant with the data protocol corresponding to an instructed frequency, for example).

Then, as shown inFIG. 2, the frame processing section40has processing sections compliant with data protocols (such as a SONET-related monitor section41, a data-related monitor section42and a video-related monitor section43), an OTU-OH (Optical Channel Transport Unit_Over Head) adding section44, an FEC (Forward Error Correction) adding section45, an OTU-OH removing section46, an FEC removing section47, a speed converting section48and a speed converting section49.

The OTU-OH adding section44adds an OTU-OH for performing frame addition processing. The FEC adding section45adds an error correction function (FEC) for performing frame addition processing. The OTU-OH removing section46removes an OTU-OH for performing frame removal processing. The FEC removing section47removes an error correction function (FEC) for performing frame removal processing. The speed converting section48and the speed converting section49perform speed conversion on a signal input to the frame processing section40. For example, the speed converting section48and the speed converting section49has a voltage controlled crystal oscillator (VCXO).

The control section100has an internal memory for storing a control program, a program defining a routine, for example, and necessary data. The control section100is a processing section that performs various routines by the programs. According to this embodiment, the control section100mainly includes a CPU section101, a frequency setting section102, a state monitoring section103, a state storage section104, a supported frequency storage section105, a speed & frequency setting data section106, and a frame processing setting data section107.

The supported frequency storage section105stores the frequency supported by the oscillating section. More specifically, the supported frequency storage section105stores all frequencies that the client side oscillating section30and/or the network side oscillating section60can output. Describing in particular, as shown inFIG. 3, the supported frequency storage section105stores on a “OSCILLATOR SUPPORTING FREQUENCY TABLE” the “HIGHEST FREQUENCY (MHz)” describing the highest frequency that the client side oscillating section30and/or the network side oscillating section60can output and the “LOWEST FREQUENCY (MHz)” describing the lowest frequency that the client side oscillating section30and/or the network side oscillating section60can output.

In the example shown inFIG. 3, the supported frequency storage section105stores “2666.325” as the “HIGHEST FREQUENCY (MHz)” and “621.9866” as the “LOWEST FREQUENCY (MHz)” on the “OSCILLATOR SUPPORTING FREQUENCY TABLE”. Notably,FIG. 3shows an example of the supported frequencies to be stored in the supported frequency storage section according to the first embodiment.

The state storage section104stores a result of the monitoring by the state monitoring section103, which will be described later. More specifically, as shown inFIG. 4, the state storage section104stores a “REFERENCE FREQUENCY (MHz) IN OSCILLATING SECTION” describing the frequency output from the client side oscillating section30to the client side CDR section21and a “CDR STATE” describing a result of the monitoring by the state monitoring section103, which will be described later, in connection with each other. The state storage section104further stores a “CENTER FREQUENCY” describing the center frequency in a frequency band calculated by the detecting section109, which will be described later, a “DEVIATION (ppm) FROM CENTER FREQUENCY” describing the deviation (ppm) from the center frequency calculated by the detecting section109, which will be described later, and a “WIDTH OF FREQUENCY BAND” describing the width of the frequency band calculated by the detecting section109, which will be described later, in connection with each other.

In the example shown inFIG. 4, the state storage section104stores “2666.325” and “Un-LOCK” as the “REFERENCE FREQUENCY (MHz) IN OSCILLATING SECTION” and the “CDR STATE”, respectively, in connection with each other. The state storage section104stores “2666.058”, “1100.3729 and −100.035” and “±100 ppm” as the “CENTER FREQUENCY”, the “DEVIATION (ppm) FROM CENTER FREQUENCY” and the “WIDTH OF FREQUENCY BAND”, respectively, in connection with each other. Notably,FIG. 4shows an example of the information on frequency synchronization stored in the state storage section according to the first embodiment.

The speed & frequency setting data section106defines the setting controlled by the frame processing control section110, which will be described later, to the speed converting section48, speed converting section49and network side oscillating section60. More specifically, information on the frequency to be set is input from the frame processing control section110to the speed & frequency setting data section106, which then defines the setting corresponding to the input frequency to the speed converting section48, speed converting section49and network side oscillating section60.

The frame processing setting data section107defines the setting controlled by the frame processing control section110, which will be described later, to the frame processing section40. More specifically, information on the frequency to be set is input from the frame processing control section110to the frame processing setting data section107, which then defines the setting corresponding to the input frequency to the frame processing section40. For example, the frame processing setting data section107defines the data protocol corresponding to the input frequency and defines the monitor section (such as the SONET-related monitor section) to be used in the frame processing section40.

The frequency setting section102defines an arbitrary frequency instructed by the frequency instructing section108, which will be described later, to the client side oscillating section30.

The state monitoring section103monitors whether the frequency output from the client side oscillating section30and an input signal synchronize in frequency or not in response to an instruction by the detecting section109, which will be described later. More specifically, in response to an instruction by the detecting section109, the state monitoring section103determines whether all of the frequencies sequentially output from the oscillating section in response to the instruction and an input signal synchronize in frequency or not and detects the frequency band for the synchronization. In particular, the state monitoring section103monitors whether the frequency output from the client side oscillating section30and an input signal synchronize in frequency (LOCK) or not and stores the “REFERENCE FREQUENCY IN OSCILLATING SECTION” and the “CDR STATE” in the state storage section104in connection with each other.

For example, the state monitoring section103outputs a frequency (such as “2666.325”) from the client side oscillating section30in response to an instruction by the detecting section109, which will be described later. After that, if the frequency and the input signal do not synchronize in frequency (LOCK), the output frequency (such as “2666.325”) and “Un-LOCK” in connection are stored in the state storage section104. In a case where a frequency (such as “2666.057”) is output from the client side oscillating section30and then synchronizes with an input signal in frequency (LOCK), the output frequency (such as “2666.057”) and “LOCK” in connection are stored in the state storage section104.

The CPU101is a control section that controls the transponder. The CPU section101has the frequency instructing section108, the detecting section109, the frame processing control section110and a frame processing monitoring section111. The frequency instructing section108and the frequency setting section102correspond to the claimed “frequency instruction processing section”. The detecting section109and the state monitoring section103correspond to the claimed “detection processing section”. The frame processing control section110, the speed & frequency setting data section106and the frame processing setting data section107correspond to the claimed “frame processing section control section”. The frame processing monitoring section111corresponds to the claimed “monitoring section”.

The frequency instructing section108instructs an oscillating section to output an arbitrary frequency. More specifically, the frequency instructing section108instructs the client side oscillating section30to sequentially output all frequencies that the client side oscillating section30can output. In particular, the frequency instructing section108instructs the client side oscillating section30to sequentially output the “HIGHEST FREQUENCY” (or the “LOWEST FREQUENCY”) through the “LOWEST FREQUENCY” (or the “HIGHEST FREQUENCY”) stored in the supported frequency storage section105.

For example, when a signal is input to the client side O/E section11, the frequency instructing section108loads the “HIGHEST FREQUENCY 2666.325” (or “LOWEST FREQUENCY 621.9866”) stored in the supported frequency storage section105(refer toFIG. 3). The frequency instructing section108instructs the frequency setting section102to sequentially output from the “HIGHEST FREQUENCY” (or the “LOWEST FREQUENCY”) loaded by the client side oscillating section30. As a result, the frequency setting section102sets a frequency to the client side oscillating section30. Then, the frequency instructing section108instructs the frequency setting section102to slightly decrease (or increase) the frequency set to the client side oscillating section30if all frequencies that the client side oscillating section30can output are not output. As a result, the frequency setting section102sets the frequency to the client side oscillating section30according to the instruction by the frequency instructing section108.

In particular, the frequency instructing section108instructs the frequency setting section102to slightly decrease (or increase) the frequency set to the client side oscillating section30if the frequency synchronization (LOCK) is detected by the detecting section109, which will be described later. On the other hand, if the frequency synchronization (LOCK) is not detected, the frequency instructing section108instructs the frequency setting section102to largely decrease (or increase) by the amount more than the amount of decrease when the frequency synchronization (LOCK) with the frequency set to the client side oscillating section30is detected. As a result, the frequency setting section102sets the frequency to the client side oscillating section30according to the instruction by the frequency instructing section108.

The detecting section109detects the synchronization frequency, which is a frequency synchronizing between the frequency output from an oscillating section in response to the instruction and an input signal. More specifically, the detecting section109detects the center frequency in the synchronizing frequency band as the synchronization frequency. If multiple synchronizing frequency bands are detected, the center frequency of the widest one of the detected multiple frequency bands is detected as the synchronization frequency.

In particular, the detecting section109detects the synchronizing frequency band based on the “REFERENCE FREQUENCY IN OSCILLATING SECTION” and “CDR STATE” stored in the state storage section104by the state monitoring section103. If one synchronizing frequency band is detected, the detecting section109detects the “CENTER FREQUENCY” in the frequency band as the synchronization frequency. If multiple synchronizing frequency bands are detected, the detecting section109calculates the “DEVIATION (ppm) FROM CENTER FREQUENCY” of the synchronization frequencies. Then, the “WIDTH OF FREQUENCY BAND (LOCK WIDTH)” is calculated, and the “CENTER FREQUENCY” describing the highest value in the calculated “FREQUENCY BAND (LOCK WIDTH)” as the synchronization frequency. In other words, the synchronization frequency is detected from the widest frequency band.

For example, describing with reference to the example shown inFIG. 4, the detecting section109detects the synchronizing frequency band (such as the frequency band at “2666.325” through “2665.79”) from the “REFERENCE FREQUENCY IN OSCILLATING SECTION” and the “CDR STATE” stored in the state storage section104by the state monitoring section103. Then, if one synchronizing frequency band is detected, the detecting section109detects the “CENTER FREQUENCY” (such as “2666.058”) as the synchronization frequency in the synchronizing frequency band (such as the frequency band at “2666.325” through “2665.79”). On the other hand, if multiple synchronizing frequency bands are detected (such as the frequency band at “2666.325” through “2665.79” and the frequency band at “622.1733 through “621.9867”), the detecting section109calculates the “CENTER FREQUENCIES” (such as “2666.058” and “622.08”) of the frequency bands. Then, the “DEVIATION (ppm) FROM CENTER FREQUENCY” of each of them is calculated, and the “WIDTH (LOCK WIDTH) OF FREQUENCY BAND” is calculated. For example, with reference to the “CENTER FREQUENCY: 2666.058”, the “DEVIATION (ppm) FROM CENTER FREQUENCY: 100.3729 through −100.035” is calculated, and the “WIDTH OF FREQUENCY BAND (LOCK WIDTH): ±100 ppm” is calculated. For example, with reference to the “CENTER FREQUENCY: 622.08”, the “DEVIATION (ppm) FROM CENTER FREQUENCY: 149.9807 through −149.981” is calculated, and the “WIDTH OF FREQUENCY BAND (LOCK WIDTH): ±150 ppm” is calculated. After that, the “WIDTHS OF FREQUENCY BAND (LOCK WIDTHS)” (such as “±100 ppm” and “±150 ppm” are compared, and the “CENTER FREQUENCY” (such as the “CENTER FREQUENCY: 622.08”) indicating the highest value (such as “±150 ppm”) in the calculated “WIDTH OF FREQUENCY BAND (LOCK WIDTH)” is detected as the synchronization frequency.

The detecting section109assumes the case where it is determined that the frame processing section40has an error in the processing based on the data protocol set by the frame processing control section110, which will be described later, and detects multiple synchronization frequencies. More specifically, in the processing of detecting synchronization frequencies, synchronization frequency candidates are also detected, which have higher possibilities of being the synchronization frequency. Then, if it is determined that the frame processing section40has an error, the detecting section109detects the synchronization frequency candidates as the multiple detected synchronization frequencies.

For example, describing with reference to the example shown inFIG. 4, the detecting section109loads and compares the “WIDTHS OF FREQUENCY BAND (LOCK WIDTHS)”, “±100 ppm” and “±150 ppm”, which are stored in connection with the “CENTER FREQUENCY” when the detecting section109detects the “CENTER FREQUENCIES” “2666.058” and “622.08”. Then, the detecting section109detects the “622.08” as the synchronization frequency and also detects “2666.058” as the synchronization frequency candidate. Then, the frame processing control section110, which will be described later, operates the frame processing section40based on the detected synchronization frequency “622.08”. After that, in a case where the frame processing monitoring section111monitors that the processing in the frame processing section40has an error, the detecting section109immediately detects the synchronization frequency candidate (such as “2666.058”) as the synchronization frequency.

The frame processing control section110operates the frame processing section based on the detected synchronization frequency. More specifically, the frame processing control section110operates the frame processing section40based on the synchronization frequency detected by the detecting section109. For example, when the detecting section109detects a synchronization frequency (such as “622.08”), the frame processing control section110controls the settings in the speed & frequency setting data section106and the frame processing setting data section107so as to perform frame processing based on the detected synchronization frequency. As a result, the speed & frequency setting data section106defines the speed converting section48, speed converting section49and network side oscillating section60(that is, sets the frequency to be output from the network side oscillating section60) under the control of the frame processing control section110. The frame processing setting data section107defines the frame processing section40under the control of the frame processing control section110. For example, the frame processing setting data section107defines the data protocol corresponding to the input frequency. The frame processing setting data section107defines the monitor section (such as the SONET-related monitor section) to be used in the frame processing section40.

The frame processing control section110operates the frame processing section based on the next synchronization frequency candidate (such as “2666.058”) in a case where the frame processing monitoring section111, which will be described later, monitors an error. On the other hand, if no subsequent synchronization frequency candidates exist, the processing ends.

The frame processing monitoring section111monitors whether the processing by the frame processing section has an error or not after the frame processing section starts operating. More specifically, after the frame processing section40starts operating under the control of the frame processing control section110, the frame processing monitoring section111monitors whether the processing by the frame processing section has an error or not. For example, the synchronization frequency “622.08” is input from the frame processing control section110to the speed & frequency setting data section106and the frame processing setting data section107. Then, the frame processing monitoring section111monitors whether the processing in the frame processing section40has an error or not after the frame processing based on the setting corresponding to the synchronization frequency “622.08” is started in the frame processing section40.

Processing by Transponder Unit

Next, with reference toFIG. 5, processing by the transponder unit will be described.FIG. 5is a flowchart showing processing by a scan method according to the first embodiment.

As shown inFIG. 5, if a signal is input to the client side O/E section (Yes in operation S101), the frequency instructing section108loads the “HIGHEST FREQUENCY” (or “LOWEST FREQUENCY”) stored in the supported frequency storage section105(operation S102). Then, the frequency is set to the oscillating section (operation S103). In other words, the frequency instructing section108instructs the frequency setting section102such that the frequency setting section102can define the client side oscillating section30to sequentially output from the “HIGHEST FREQUENCY” (or “LOWEST FREQUENCY”) loaded from the supported frequency storage section105. Then, the client side oscillating section30outputs the set frequency (operation S104).

Then, the state monitoring section103determines whether the input signal synchronizes with the frequency or not (operation S105). Here, if the input signal synchronizes with the frequency (LOCK) (Yes in operation S105), the state monitoring section103stores the output frequency (such as “2666.057”) in connection with “LOCK” in the state storage section104(operation S106). On the other hand, if the input signal does not synchronize with the frequency (Un-LOCK) (No in operation S105), the state monitoring section103stores the output frequency (such as “2666.325”) in connection with “Un-Lock” in the state storage section104(operation S107).

Then, the frequency instructing section108determines whether all of the frequencies that the client side oscillating section30can output have been examined or not (operation S108). Here, if all of the frequencies have not been examined (No in operation S108), that is, all of the frequencies have not been output from the client side oscillating section30in response to the instruction by the frequency instructing section108, the frequency instructing section108instructs the frequency setting section102to slightly decrease (or increase) the frequency set to the client side oscillating section30(operation S109). Then, the detecting section109examines the reset frequencies (operations S103to S107).

Then, if all of the frequencies that the client side oscillating section30can output have been output in response to the instruction by the frequency instructing section108, and one synchronizing frequency band is detected (Yes in operation S108and Yes in operation S110), the detecting section109detects the “CENTER FREQUENCY” in the frequency band as the synchronization frequency (operation S111).

On the other hand, if all of the frequencies that the client side oscillating section30can output have been output in response to the instruction by the frequency instructing section108and multiple synchronizing frequency bands are detected (Yes in operation S108and No in operation S110), the detecting section109calculates the widths of the frequency bands (operation S112). That is, the “DEVIATION (ppm) FROM CENTER FREQUENCY” of each of the synchronizing frequencies is calculated, and the “WIDTH OF FREQUENCY BAND (LOCK WIDTH)” is calculated. Then, the detecting section109detects the synchronization frequency from the widest frequency band (operation S113). That is, the “CENTER FREQUENCY” indicating the highest value among the calculated “WIDTHS OF FREQUENCY BANDS (LOCK WIDTHS)” is detected as the synchronization frequency. Then, the detecting section109detects the synchronization frequency and detects a synchronization frequency candidate (operation S114).

Then, the frame processing control section110operates the frame processing section based on the detected synchronization frequency (operation S115). Then, the frame processing monitoring section111monitors whether the frame processing section40has an error or not (operation S116). Here, if an error in the frame processing section is monitored and there is a synchronization frequency candidate (Yes in operation S116and Yes in operation S117), that is, if the frame processing monitoring section111, which will be described later, monitors that the processing in the frame processing section40has an error and the detecting section109has detected a synchronization frequency candidate, the detecting section109detects the synchronization frequency candidate (such as “2666.058”) as the synchronization frequency (operation S118).

Then, if the frame processing section does not have an error (No in operation S116) or if the frame processing section has an error but no synchronization frequency candidate exists (Yes in operation S116but No in operation S117), the processing ends.

Effects of First Embodiment

As described above, according to the first embodiment, the transponder unit instructs an oscillating section to output an arbitrary frequency. Then, whether the frequency output from the oscillating section in response to the instruction and an input signal synchronize in frequency or not is determined, and the synchronization frequency is detected. Then, the frame processing section is operated based on the detected synchronization frequency. Thus, the transponder unit can detect the synchronizing frequency from an input signal and control the operation by the frame processing section. Therefore, the manual work for defining a data protocol to be used in the client can be reduced.

Further, according to the first embodiment, the transponder unit instructs an oscillating section to sequentially output all frequencies that the oscillating section can output. Then, whether each of all of the frequencies sequentially output from the oscillating section in response to the instruction synchronizes with an input signal or not is determined, and the synchronizing frequency band is detected. Since the transponder unit detects the center frequency in the synchronizing frequency band as the synchronization frequency, the synchronizing frequency can be detected by examining all of the supported frequencies, and the operation by the frame processing section can be controlled. Then, the manual work for defining a data protocol to be used in the client can be reduced.

According to the first embodiment, the transponder unit detects the center frequency in the widest frequency band among multiple detected frequency bands as the synchronization frequency if multiple synchronizing frequency bands are detected. Therefore, the frequency with the highest possibility of synchronizing most accurately among them can be detected even if multiple frequencies which synchronize with an input signal are detected.

According to the first embodiment, the transponder unit monitors whether the processing by the frame processing section has an error or not after the frame processing section starts operating and detects the synchronization frequency again if the occurrence of an error is determined. Then, the frame processing section is operated based on the synchronization frequency detected again. Therefore, an accurate synchronization frequency can be detected again even if an improper synchronization frequency is detected, and the operation can be controlled securely based on an input signal.

According to the first embodiment, the transponder unit also detects a synchronization frequency candidate, which is a frequency with a higher possibility of being a synchronization frequency, in detecting the synchronization frequency. Then, if the occurrence of an error is determined, the synchronization frequency candidate is detected as the synchronization frequency detected again. Therefore, quick processing can be implemented by defining other synchronization frequency candidate and controlling the operation even if an improper synchronization frequency is detected.

Second Embodiment

Having described the first embodiment where a synchronization frequency is detected by examining the synchronization with all of supported frequencies, embodiments are not limited thereto. A synchronization frequency may be detected by sampling an input signal. A case where a synchronization frequency is detected by sampling an input signal will be described as a second embodiment. The identical points to those of the transponder unit according to the first embodiment will be described briefly.

Configuration of Transponder Unit According to Second Embodiment

First of all, with reference toFIG. 6, a configuration of a transponder unit according to a second embodiment will be described.FIG. 6is a block diagram showing a configuration of the transponder unit according to the second embodiment. As shown inFIG. 6, a transponder unit1includes a client side input/output section10, a client side CDR & DRV section20, a client side oscillating section30, a frame processing section40, a network side CDR & DRV section50, a network side oscillating section60, a network side input/output section70, a sampling oscillating section80that outputs a sampling frequency to be used for sampling by a detecting section109b, which will be described later, and a control section100.

The same reference numerals are given to the same operations as those of the first embodiment, the description of which will be omitted herein. The sampling oscillating section80, a frequency instructing section108b, a detecting section109b, a sampling section112and a frequency calculating section113will be only described.

The sampling oscillating section80outputs a sampling frequency, which is a frequency set for sampling, to the sampling section112in response to the instruction by the frequency instructing section108b, which will be described later.

This embodiment describes a case where the sampling oscillating section80is provided separately from the client side oscillating section30and/or the network side oscillating section60. However, this embodiment is not limited to the case, in the alternative, the sampling oscillating section80may be provided unitedly with the client side oscillating section30and/or the network side oscillating section60and may output a sampling frequency to the sampling section112.

The sampling section112samples an input signal by using the sampling frequency in response to the instruction by the frequency instructing section108b, which will be described later. For example, as described inFIG. 7A, the sampling frequency is used to obtain the sampling result including “0” and “1” (such as “0, 0, 1, 1, 1, 1, 1, 1 . . . inFIG. 7A) from the signal electrically converted by the client side O/E section11in response to the instruction by the frequency instructing section108b, which will be described later.

The frequency calculating section113identifies points of change from the sampling result in response to the instruction by the frequency instructing section108b, which will be described later. After that, the frequency calculating section113calculates the point-of-change cycle frequency, which is a point-of-change cycle, from the value of the sampling frequency and the points of change.

For example, as described inFIG. 7Bthe frequency calculating section113identifies the points of change where “0” is changed to “1” (or “1” to “0”) based on the sampling result (such as “0, 0, 1, 1, 1, 1, 1, 1 . . . ” inFIG. 7A) including “0” and “1” in response to the instruction by the frequency instructing section108b, which will be described later. The sampling result is detected in the sampling section112(refer to the arrow inFIG. 7B). After that, as described inFIG. 7C, the point-of-change cycle frequency is calculated (such as 2 GHz/16=0.125 GHz=125 MHz) from the sampling result (such as “0, 0, 1, 1, 1, 1, 1, 1 . . . ”), the sampling frequency (such as 2 GHz) and the points of change (such as a cycle of 16).

The frequency instructing section108bsamples an input signal by using the sampling frequency, identifies the points of change from the sampling result, and calculates the point-of-change cycle frequency, which is a cycle of points of change, from the value of the sampling frequency and the points of change. Then, the frequency instructing section108bfurther instructs the oscillating section to output the calculated point-of-change cycle frequency.

For example, when a signal is input to the client side O/E section, the frequency instructing section108binputs the input signal to the sampling section112. Then, the sampling oscillating section80instructs the sampling section112to output a sampling frequency. As a result, the sampling oscillating section80outputs the sampling frequency to the sampling section112.

Then, the frequency instructing section108binstructs the sampling section112to sample the input signal. As a result, the sampling section112samples the input signal (refer toFIG. 7A). Then, the frequency instructing section108binstructs the frequency calculating section113to identify points of change from the obtained sampling result and calculate the point-of-change cycle frequency. As a result, the frequency calculating section113identifies the points of change from the obtained sampling result.

Then, the frequency calculating section113calculates the point-of-change cycle frequency from the obtained sampling result, the sampling frequency (such as 2 GHz) and points of change (such as a cycle of 16). In other words, the frequency calculating section113calculates a frequency with a higher possibility of being a point-of-change cycle frequency from the sampling result, the sampling frequency and the points of change. The frequency calculating section113further calculates, as the point-of-change cycle frequency the frequency closest to the frequency information stored in the supported frequency storage section105.

Then, the frequency instructing section108binstructs the frequency setting section102to output the calculated point-of-change cycle frequency from the client side oscillating section30. The frequency instructing section108bassumes a case where outputting a harmonic of the point-of-change cycle frequency calculated by the detecting section109b, which will be described later, from the client side oscillating section30is instructed and calculates the harmonic as a synchronization frequency candidate from the calculated point-of-change cycle frequency.

With reference toFIGS. 8A to 8D, for example, the calculation of a harmonic by the frequency instructing section108bwill be described. The frequency instructing section108bis instructed to calculate a harmonic by the detecting section109b, which will be described later. The frequency instructing section108b, as shown inFIG. 8A, determines that the point of change cycle frequency (such as 125 MHz) calculated from the sampling result (such as “0, 0, 1, 1, 1, 1, 1, 1 . . . ”), the sampling frequency (such as 2 GHz) and the points of change (such as a cycle of 16) is a bit rate of a low frequency. In other words, as shown inFIGS. 8A to 8D, the frequency instructing section108bdetermines that it is not the cycle of an input signal (which is a cycle that “1” and “0” change alternately).

As a result, as shown inFIGS. 8C and 8D, the frequency instructing section108bdetermines that the calculated point-of-change cycle frequency is a frequency exhibiting the cycle of a series of multiple “1” or “0” and calculates a harmonic as a synchronization frequency candidate. In other words, in the example shown inFIG. 8C, for example, the frequency instructing section108bdetermines the frequency having a series of two “1” and two “0” and calculates 250 MHz, which is twice as high as 125 MHz. In the example shown inFIG. 8D, the frequency instructing section108bdetermines the frequency having a series of three “1” and “0” and calculates 375 MHz, which is triple as high as 125 MHz.

The frequency instructing section108binstructs the frequency setting section102to output the calculated harmonic from the client side oscillating section30in response to the instruction to output the harmonic of the point-of-change cycle frequency calculated by the detecting section109, which will be described later, from the client side oscillating section30.

The detecting section109bdetermines whether the point-of-change cycle frequency output from the oscillating section in response to the instruction and an input signal synchronize in frequency or not. If so as a result of the determination, the point-of-change cycle frequency is detected as the synchronization frequency. If not, on the other hand, the detecting section109bcauses the frequency instructing section108bto set the harmonic of the point-of-change cycle frequency to the oscillating section and determines whether the harmonic and an input signal synchronize in frequency or not again.

More specifically, the detecting section109bdetermines whether the point-of-change cycle frequency (such as 125 MHz) output by the client side oscillating section30and an input signal synchronize in frequency or not. Then, if so, the detecting section109bdetects the point-of-change cycle frequency (such as 125 MHz) as the synchronization frequency. If not, on the other hand, the detecting section109bcauses the frequency instructing section108bto calculate a harmonic of the point-of-change cycle frequency (such as 250 MHz), causes the client side oscillating section30to output the harmonic and performs the determination again.

Processing By Sampling Method According To Second Embodiment

Next, with reference toFIG. 9, the processing by the sampling method according to the second embodiment will be described.FIG. 9is a flowchart showing processing by the sampling method according to the second embodiment.

The frequency instructing section108binputs the input signal to the sampling section112(operation S202) in response to a signal input to the client side OIL/E section11(Yes in operation S201). Then, the frequency instructing section108bsamples the input signal (operation S203). In other words, the frequency instructing section108binstructs the sampling oscillating section80to output a sampling frequency to the sampling section112and instructs the sampling section112to sample the input signal (refer to (1) inFIG. 7A).

Then, the frequency instructing section108bidentifies the points of change (operation S204). In other words, the frequency instructing section108instructs the frequency calculating section113to identify the points of change from the obtained sampling result. Then, the frequency instructing section108bcalculates the point-of-change cycle frequency (operation S205). In other words, the frequency instructing section108binstructs the frequency instructing section108bto calculate the point-of-change cycle frequency from the obtained sampling frequency (such as 2 GHz) and the point of change (such as a cycle of 16). Then, the frequency instructing section108bdetects the synchronization frequency and also detects a synchronization frequency candidate (operation S206). Then, the frequency instructing section10binstructs the frequency setting section102to define the client side oscillating section30to output the detected point-of-change cycle frequency (operation S207). Then, the client side oscillating section30outputs the set frequency (operation S208).

Then, the detecting section109bdetermines whether the set frequency can be the synchronization frequency or not (operation S209). Here, if so (Yes in operation S209), the detecting section109bdetects the point-of-change cycle frequency (such as 125 MHz) as the synchronization frequency (operation S211). If not, on the other hand (No in operation S209), the detecting section109bsets a harmonic (operation S210) and causes to output the set frequency and determines the synchronization in frequency (operation S208to S209). In other words, the detecting section109bcauses the frequency instructing section108bto calculate a harmonic of the point-of-change cycle frequency and causes to output the frequency from the client side oscillating section30and performs the determination again.

Then, the frame processing control section110performs frame processing based on the detected synchronization frequency and exits the processing (operation S212to the end).

Effects of Second Embodiment

As described above, according to the second embodiment, the transponder unit samples an input signal by using a sampling frequency, identifies points of change from the sampling result, calculates the point-of-change cycle frequency from the value of the sampling frequency and the points of change, instructs an oscillating section to output the point-of-change cycle frequency, determines whether the point-of-change cycle frequency output from the oscillating section in response to the instruction and an input signal synchronize in frequency or not and, if so, detects the point-of-change cycle frequency as the synchronization frequency. If not, on the other hand, a harmonic of the point-of-change cycle frequency is set to the oscillating section through frequency instructing means, and whether the frequency synchronizes with an input signal or not is determined again. Therefore, the transponder unit can securely detect the frequency in synchronization with an input signal and can control operations. The transponder unit further can detect the synchronizing frequency accurately independent of the state of data (such as a series of multiple “1”) at the sampled frequency. The transponder unit further can reduce the manual work for defining the data protocol to be used in a client.

Third Embodiment

Having described the transponder units according to the first and second embodiments above, embodiments may be implemented in various different forms excluding the embodiments above. A transponder unit according to a third embodiment in a different form will be described below.

Having described the first and second embodiments in which the processing section corresponding to each data protocol can operate at all times, embodiments are not limited thereto. After the setting relating to an input signal is performed, unnecessary processing sections may be terminated.

More specifically, a transponder unit may terminate a processing section, which is not necessary for the processing based on a synchronization frequency, in a case where a frame processing section is operated based on the synchronization frequency. For example, describing with reference to the example shown inFIG. 2, in a case where an input signal is SONET-related data and in a case where the frame processing section40is controlled by the frame processing control section110based on the setting corresponding to the SONET-related data, the data-related monitor section42and video-related monitor section43are terminated, which are unnecessary processing sections for the processing based on SONET-related data.

In this way, the transponder unit terminates an unnecessary processing section for the processing based on a synchronization frequency in a case where a frame processing section is operated based on the synchronization frequency. Therefore, the energy consumption by the transponder unit can be reduced, which can implement the processing with a higher energy efficiency.

Having described the first embodiment in a case where the transponder unit detects a synchronization frequency and also detects a synchronization frequency candidate, embodiments are not limited thereto. If the occurrence of an error is determined, a synchronization frequency may be detected again from the beginning. Having described the case where the occurrence of an error is monitored by the frame processing monitoring section111and processing ends if no synchronization frequency candidate is detected, embodiments are not limited thereto. A synchronization frequency may be detected again from the beginning.

The components of the shown apparatus are functionally conceptual and do not always have to be physically configured as shown. In other words, the specific forms of the distribution/unity of apparatus are not limited to those shown in the figures. All or a part of the shown components may be physically distributed or united functionally or physically in arbitrary units according to the various loads and state of use (for example, inFIG. 2, the frequency setting section102and the frequency instructing section108may be united, the state monitoring section103and the detecting section109may be united, the speed & frequency setting data section106, the frame processing setting data section107and the frame processing control section110may be united, and the transponder unit1and the control section100may be separated). All or any part of the processing functions to be performed in the apparatus may be implemented by a CPU and programs to be analyzed and executed by the CPU or may be implemented as hardware based on Wired Logic.

Program for Transponder Unit

Having described the case where the processing is implemented by a hardware logic according to the first embodiment, embodiments are not limited thereto. The processing may be implemented by executing a prepared program in a computer. With reference toFIG. 10, an example of a computer that executes a transponder unit control program having the same functions as those of the transponder unit according to the first embodiment will be described.FIG. 10is a diagram showing a program for the transponder unit according to the first embodiment.

As shown inFIG. 10, a transponder unit includes a client side E/O section3001, a client side O/E section3002, a client side CDR & DRV section3003, a frame processing section3004, a network side E/O section3005, a network side O/E section3006, a network side CDR & DRV section3007, a CPU3110, a ROM3111, an HDD3112and a RAM3113, which are connected via a bus3008.

The ROM3111stores control programs that function the same as those of the frequency instructing section108, the detecting section109, the frame processing control section110, and the frame processing monitoring section111according to the first embodiment. In other words, as shown inFIG. 10, the ROM3111prestores a frequency instruction program3111a, a detection program3111b, a frame processing control program3111cand a frame processing monitoring program3111d. Notably, these programs3111ato3111dmay be united or separated as required, like the components of the transponder unit shown inFIG. 2.

The CPU3110loads and executes the programs3111ato311dfrom the ROM3111so that the programs3111ato3111dcan function as a frequency instruction process3110a, a detection process3110b, a frame processing control process3110cand a frame processing monitoring process3110d, as shown inFIG. 10. The processes3110ato3110dcorrespond to the frequency instructing section108, the detecting section109, the frame processing control section110and the frame processing monitoring section111, respectively, shown inFIG. 2.

The CPU3110further executes a transponder control program based on synchronization frequency data3113aand supported frequency data3113bstored in the RAM3113.

It should be noted that the programs3111ato3111daccording to this embodiment are not always required to store in the ROM from the beginning. For example, the programs may be stored in a “portable physical medium” such as a memory card, a flexible disk, a CD-ROM, an MO disk, a DVD, a magnetooptical disk and an IC card to be inserted to the transponder unit, a “fixed physical medium” such as an HDD internally or externally provided to the transponder unit or “other computer (or server)” connecting to the transponder unit over a public line, the Internet, a LAN or WAN, for example. Then, the transponder unit may load and execute the programs from the medium.