JP7175931B2 - Measuring device and measuring method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a measuring apparatus and a measuring method having a function of informing a measurement-impossible state when measuring a signal under measurement transmitted from an object under test.

For example, an error rate measuring device, a sampling oscilloscope, and the like are known as devices for measuring signals transmitted by a device under test (DUT) 70 such as various devices.

For example, as disclosed in Patent Document 1, an error rate measuring apparatus has clock recovery means for recovering a clock signal from a signal under test input via a device under test, and based on the recovered clock signal, calculating an error rate by comparing the identification pattern data of the signal under measurement and the reference pattern, and determining that the reference pattern and the signal under measurement are in pattern synchronization when the calculated error rate is below the reference error rate threshold; 2. Description of the Related Art Conventionally, there has been known a method for displaying a signal waveform for waveform observation of a signal under measurement.

JP 2011-146791 A

In the conventional error rate measuring apparatus described above, when a pattern is generated at a transmission rate different from the transmission rate assumed by the device under test, the clock recovery means cannot recover the clock signal. Measurement (waveform observation, bit error rate measurement) may become impossible.

In this conventional error rate measuring apparatus, no consideration has been given to informing the user of the impossibility of measurement due to erroneous setting of measurement conditions. For this reason, with conventional error rate measurement equipment, if a device under test generates an unexpected transmission rate and becomes unable to measure (waveform observation, bit error rate measurement), the user can identify the cause. Therefore, there was a problem that the measurement (waveform observation, bit error rate measurement) could not be started immediately.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such conventional problems, and is a measuring apparatus that enables a user to easily identify the cause of a state in which measurement is impossible, and to quickly return to a state in which measurement is possible. , and to provide a measurement method.

In order to solve the above-mentioned problems, a measuring apparatus according to claim 1 of the present invention comprises clock recovery means (3) for receiving a signal under measurement and recovering a clock signal synchronized with the signal under measurement; setting means (9) for setting a transmission rate in association with a signal; transmission rate detection means (5f) for detecting the transmission rate of the input signal under measurement; and the transmission rate set by the setting means and the transmission rate. and notification means (5g) for notifying that the measurement is impossible when the transmission rates detected by the detection means are different , wherein the clock reproduction means generates the clock signal having an oscillation frequency corresponding to the input voltage. and phase comparison means (3c) for sending a voltage corresponding to the phase difference signal between the signal under measurement and the clock signal to the voltage controlled oscillator as the input voltage. a circuit section (3e), wherein the transmission rate detection means detects the transmission rate based on the count value of the clock signal when the PLL circuit section is locked by phase shift control of the clock signal input to the phase comparison means; The transmission rate is detected, and the notification means displays a state indicating that the PLL circuit section is in an unlocked state while the value of the set transmission rate is being displayed. and

With this configuration, the measuring apparatus according to claim 1 of the present invention notifies that the measurement is impossible if the set transmission rate and the actually detected transmission rate are different when measuring the signal under measurement. , the user can easily notice the cause of the unmeasurable state, and can quickly take measures to restore the measurable state.

Further, with this configuration, the measuring apparatus according to claim 1 of the present invention can utilize the existing functions of the clock recovery means and realize the transmission rate detection means with a simple configuration.

In addition, with this configuration, the measuring apparatus according to claim 1 of the present invention detects that the set transmission rate is different from the detected transmission rate, and when the PLL circuit section does not lock, the user can detect whether or not the clock recovery means is locked. It is easy to notice that measurement is impossible due to

Further, in the measuring apparatus according to claim 2 of the present invention, when the PLL circuit unit is in a locked state at a transmission rate different from the set transmission rate, the notification means notifies the detected transmission rate to It may have a configuration for displaying a notification message that includes the indicated numerical value and prompts confirmation of the detected transmission rate.

With this configuration, the measuring apparatus according to claim 2 of the present invention prompts confirmation of the transmission rate that enables locking even when the set transmission rate and the detected transmission rate are different, and depending on the situation, It becomes possible to shift to the measurement operation in the setting state of .

Moreover, in the measuring device according to claim 3 of the present invention, the notification means may be configured to highlight the notification message using at least one of a font of a specific color and blinking.

With this configuration, when the measuring apparatus according to claim 3 of the present invention enters a locked state at a transmission rate different from the set transmission rate, the transmission rate at which locking is possible can be reliably confirmed, and the user can It is possible to encourage prompt response after that.

Further, in the measuring apparatus according to claim 4 of the present invention, an amplitude detection means (2A, 5h) for detecting the amplitude of the input signal under measurement , and a notification control function based on the amplitude are added to the notification means. and a notification control section (5g1) , wherein the notification control section is configured to control the amplitude of the signal under measurement when the amplitude of the signal under measurement is smaller than an amplitude value set corresponding to the signal under measurement. It may be configured to notify that measurement is impossible due to an amplitude abnormality of the signal.

With this configuration, the measuring apparatus according to claim 4 of the present invention can quickly eliminate the state in which measurement is impossible due to the small amplitude of the signal under measurement, and can also provide erroneous measurement results when the amplitude of the signal under measurement is small. can be avoided.

Further, in the measuring apparatus according to claim 5 of the present invention, the amplitude detecting means converts the signal under measurement transmitted as an optical signal into an electrical signal and outputs the electrical signal, while corresponding to the optical power of the optical signal. and an amplitude detection control means (5h) for detecting the amplitude of the signal under measurement based on the electrical signal corresponding to the optical power. .

With this configuration, the measuring apparatus according to claim 5 of the present invention can realize the amplitude detection means with a simple configuration by using the optical power detection function of the existing photoelectric conversion means.

A measuring apparatus according to claim 6 of the present invention is a waveform observing apparatus comprising waveform observing means (4) for observing the waveform of the signal under measurement using the clock signal reproduced by the clock reproducing means. wherein the setting means sets a transmission rate in association with the signal under measurement whose waveform is observed, and when the transmission rate set by the setting means and the transmission rate detected by the transmission rate detection means are different, The notification means may be configured to notify that the waveform cannot be observed.

With this configuration, in the measuring apparatus according to claim 6 of the present invention, when observing the waveform of the signal under measurement by the waveform observing means, the transmission rate set in association with the signal under measurement whose waveform is observed and the transmission rate actually detected If the transmission rate is different, the user is notified that waveform observation is not possible, so the user can easily find out the cause of the waveform observability condition, and can quickly respond to return to the waveform observable condition. Become.

A measuring apparatus according to claim 7 of the present invention is an error rate measuring apparatus which measures the bit error rate of the signal under measurement using the clock signal reproduced by the clock reproducing means. A measurement unit (4a) is further provided, wherein the setting means sets a transmission rate in association with the signal under measurement whose bit error rate is to be measured, and is detected by the transmission rate set by the setting means and the transmission rate detection means. When the transmitted transmission rates are different, the notification means may be configured to notify that the bit error rate cannot be measured.

With this configuration, the measuring apparatus according to claim 7 of the present invention, when measuring the bit error rate of the signal under measurement by the bit error rate measuring unit, can be set to the transmission rate set in association with the signal under measurement whose bit error rate is to be measured. If the actually detected transmission rate is different, the fact that the bit error rate cannot be measured is notified, so that the user can easily notice the cause of the bit error rate measurement impossible state, and the bit error rate can be measured. A quick response to return to the state becomes possible.

Further, the measuring method according to claim 8 of the present invention has a clock recovery means (3) for receiving a signal under measurement and recovering a clock signal synchronized with the signal under measurement, wherein the clock recovery means inputs A voltage controlled oscillator (3a) that outputs the clock signal having an oscillation frequency corresponding to the voltage, and a voltage corresponding to a phase difference signal between the signal under measurement and the clock signal is sent to the voltage controlled oscillator as the input voltage. and a PLL circuit section (3e) having a phase comparison means (3c) for measuring the signal under measurement using the clock signal output from the voltage controlled oscillator, the method comprising: A setting step (S1) for setting a transmission rate in association with a measurement signal; a transmission rate detection step (S4) for detecting the transmission rate of the input signal under measurement; and a transmission rate set in the setting step and the transmission. and a notification step (S10) of notifying that measurement is impossible when the transmission rates detected in the rate detection step are different , wherein the transmission rate detection step inputs the data to the phase comparison means. The transmission rate is detected based on the count value of the clock signal when the PLL circuit unit is locked by the phase shift control of the clock signal, and the notification step includes displaying the set transmission rate value. and displaying a state indicating that the PLL circuit section is in an unlocked state, further comprising an amplitude detection step (S22) for detecting the amplitude of the input signal under measurement, wherein the notification step is and, if the amplitude of the signal under measurement is smaller than the amplitude value set corresponding to the signal under measurement, further reporting that the measurement is impossible due to the amplitude abnormality of the signal under measurement (S24) . Characterized by

With this configuration, the measurement method according to claim 8 of the present invention notifies that measurement is impossible when the set transmission rate differs from the actually detected transmission rate when measuring the signal under measurement. , the user can easily notice the cause of the unmeasurable state, and can quickly take measures to restore the measurable state. In addition, with this configuration, the measurement method according to claim 8 of the present invention is such that when the set transmission rate is different from the detected transmission rate and the PLL circuit section does not lock, the user can detect whether or not the clock recovery means is inadequately locked. It is easy to notice that measurement is impossible due to Further, with this configuration, the measurement method according to claim 8 of the present invention can quickly eliminate the state in which measurement is impossible due to the small amplitude of the signal under measurement, and can also eliminate erroneous measurements due to the small amplitude of the signal under measurement. It is also possible to avoid getting results.

Further, in the measuring method according to claim 9 of the present invention, in the reporting step, when the PLL circuit unit is locked at a transmission rate different from the set transmission rate, the detected transmission rate is A configuration may also be adopted in which a notification message is displayed that includes the indicated numerical value and prompts confirmation of the detected transmission rate . With this configuration, the measurement method according to claim 9 of the present invention prompts confirmation of the transmission rate at which locking is possible even when the set transmission rate and the detected transmission rate are different. It becomes possible to shift to the measurement operation in the setting state of .

In the measuring method according to claim 10 of the present invention , the notification means may highlight the notification message using at least one of a font of a specific color and blinking. With this configuration, in the measuring method according to claim 10 of the present invention, when a locked state occurs at a transmission rate different from the set transmission rate, the transmission rate at which locking becomes possible is reliably confirmed, and the user is notified of the transmission rate. It is possible to encourage prompt response after that.

INDUSTRIAL APPLICABILITY The present invention can provide a measuring apparatus and a measuring method that allow a user to easily identify the cause of the unmeasurable state and quickly return to the measurable state.

1 is a configuration diagram of a measuring device according to a first embodiment of the present invention; FIG. 3 is a block diagram showing the configuration of a clock recovery circuit of the measuring device according to the first embodiment of the present invention; FIG. FIG. 4 is a diagram showing a clock signal reproduction image of the clock recovery circuit of the measuring device according to the first embodiment of the present invention; It is a block diagram showing a functional configuration of a control unit of the measuring device according to the first embodiment of the present invention. FIG. 3 is a diagram showing the configuration of a display function unit for notifying a measurement impossible state due to an erroneous setting of a transmission rate in the measuring device according to the first embodiment of the present invention; FIG. 4 is a diagram showing the configuration of a display function unit for notifying that confirmation of a transmission rate is prompted in the measuring device according to the first embodiment of the present invention; 4 is a flow chart showing the measurement/waveform observation processing operation of the measuring device according to the first embodiment of the present invention; FIG. 7 is a block diagram showing the configuration of a clock recovery circuit of the measuring device according to the second embodiment of the present invention; It is a block diagram which shows the functional structure of the control part of the measuring device which concerns on the 2nd Embodiment of this invention. 9 is a flow chart showing the measurement/waveform observation processing operation of the measuring device according to the second embodiment of the present invention.

Embodiments of a measuring apparatus and a measuring method according to the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing the configuration of a measuring device 1 according to the first embodiment of the present invention. This measuring apparatus 1 includes a photoelectric converter (O/E) 2, a clock recovery unit (CRU) 3, a waveform observing section 4, an error rate measuring section 4a, a switching section 4b, a control section 5, and a storage section 6. , an operation unit 7 and a display unit 8 .

The measuring apparatus 1 connects a device under test (DUT) 50, inputs a data signal output by the DUT 50, generates a clock signal synchronized with the data signal from the input data signal, and generates The data signal is measured (bit error rate measurement) and the waveform of the data signal is observed based on the clock signal.

As the DUT 50, various optical devices (or optical modules) such as an optical transceiver and an optical interface having a function of transmitting optical signals are used. The DUT 50 is of various types that can transfer an optical signal having any transmission rate (standard rate) among a plurality of transmission rates to which respective standards are allocated, or an optical signal having an arbitrary transmission rate. is prepared. The measuring apparatus 1 selectively connects (exchanges) various types of DUTs 50 capable of passing optical signals of each standard rate or optical signals of any transmission rate, and outputs optical signals from the DUTs 50. It is designed to observe the waveform of (signal under test) and measure the bit error rate.

As shown in FIG. 1, for an optical device measurement system using a measurement apparatus 1, a signal generator (Pulse Pattern Generator: PPG) 10 is arranged in front of a DUT 50, and the DUT 50 generates a data signal (reference data) from the PPG 10. is input and the data signal is output to the measuring device 1 as an optical signal.

In the measuring device 1, the data signal (optical signal) sent from the DUT 50 is converted into an electrical signal by the O/E 2 and input to the clock recovery circuit 3, the waveform observing section 4, or the error rate measuring section 4a. The clock recovery circuit 3 reproduces a clock signal from the input data signal and outputs the clock signal to the waveform observing section 4 or the error rate measuring section 4a via the switching section 4b. The waveform observation unit 4 samples the data signal input via the O/E 2 at sampling timing corresponding to the clock signal input from the clock recovery circuit 3 to observe the waveform. Using the clock signal input from the clock recovery circuit 3, the error rate measuring unit 4a measures the bit error rate of the data signal input via the O/E 2. FIG. In this embodiment, the waveform observation unit 4 and the error rate measurement unit 4a are switchable by the switching unit 4b. 4a may simply be a branched configuration. Furthermore, the configuration may be such that the waveform observation unit 4 and the error rate measurement unit 4a are integrated.

The configuration of each part of the measuring device 1 will be described in detail below. In the measurement apparatus 1, the O/E 2 includes, for example, a photodiode as a photodetector, and converts an optical signal output by the DUT 50 as a signal under measurement (data signal) into an electrical signal. The O/E 2 is necessary when the specification of the DUT 50 is to output an optical signal based on the input of an electrical signal, and the specification is such that the DUT 50 outputs an electrical signal based on the input of an optical signal. is not required if

A clock recovery (CR) circuit 3 receives a data signal (Data) converted into an electric signal by the O/E 2, reproduces and outputs a clock signal (Clock) synchronized with the data signal. For example, as shown in FIG. 2, the clock recovery circuit 3 includes a voltage controlled oscillator (VCO) 3a, a phase shifter (PS) 3b, a phase detector (PD) 3c, a low-pass It has a filter (Low-pass filter: LPF) 3d.

The VCO 3a outputs a signal with an oscillation frequency corresponding to the input voltage. Specifically, the VCO 3a receives the voltage corresponding to the phase error signal between the phase of the data signal input from the DUT 50 and the clock signal output from the VCO 3a from the phase comparator 3c via the LPF 3d, and the input voltage The clock signal having the corresponding oscillation frequency is re-output.

The phase shift circuit 3b has a terminal 3b1 for inputting an external control voltage, and shifts the clock from the VCO 3a based on the DC control voltage (DC input) input as a phase correction value from the control unit 5 to the terminal 3b1. The phase of the signal is shifted, and the phase-shifted clock signal is input to the phase comparator 3c.

The phase comparator 3c compares the phase of the data signal input from the DUT 50 via the O/E 2 with the phase of the clock signal output after the phase shift from the phase shift circuit 3b, and outputs a phase error signal between the two. .

The LPF 3d filters the phase error signal output from the phase comparator 3c so as to pass only frequencies below a specified frequency and smoothes the signal, and outputs it as the input voltage to the VCO 3a. The VCO 3a re-outputs a clock signal having a frequency corresponding to the input voltage from the LPF 3d.

Thus, the clock recovery circuit 3 includes the VCO 3a that outputs a clock signal having an oscillation frequency corresponding to the input voltage, and the phase difference between the input data signal (input signal: signal under measurement) and the clock signal output by the VCO 3a. A PLL circuit section 3e having a phase comparator 3c that detects a signal and sends a voltage corresponding to the phase difference signal to the VCO 3a as an input voltage, and an LPF 3d that generates a voltage corresponding to the phase difference signal. there is In the clock recovery circuit 3, the sweep control of the phase correction value (DC input value) used for the phase shift control for sequentially shifting the phase of the clock signal input to the phase comparator 3c is repeated until the PLL circuit section 3e is locked. implemented to synchronize the clock signal with the input signal.

The control section 5 controls the phase shift of the clock signal in the phase shift circuit 3b. In this control, when a data signal (signal under measurement) is input to the clock recovery circuit 3, the control unit 5 performs sweep control of the phase correction value (DC input value) input from the terminal 3b1 to the phase shift circuit 3b. is repeated until the lock of the PLL circuit section 3e is detected. More specifically, when a data signal is input, the control unit 5 changes the DC input value to a preset sweep voltage range (for example, 5 V range) until the PLL circuit unit 3e locks the DC input value to a predetermined voltage width. (For example, 0.1 V), the same routine is repeated every time.

FIG. 3 is a diagram showing a clock signal reproduction image of the clock recovery circuit 3 of the measuring device 1 according to this embodiment. As shown in FIG. 3, in the measuring apparatus 1, the clock recovery circuit 3 receives a data signal (signal under measurement) sent from the DUT 50, and converts the data signal into a clock synchronized with the data signal. ) to reproduce and output the signal. In FIG. 3, four PAM (Pulse-Amplitude Modulation) signals having a transmission rate of, for example, 53 Gbaud are input as data signals, and a clock signal of, for example, 6.6 GHz synchronized with the data signals is reproduced. is mentioned. The clock recovery circuit 3 can handle not only PAM4 signals, but also PAM8 signals or NRZ (Non Return to Zero) signals having PRBS patterns, and can adapt to various transmission rates (regulated rates). is.

The waveform observation unit 4 receives the data signal output from the O/E 2 and the clock signal output from the clock recovery circuit 3 (output when the PLL circuit unit 3e is locked), and detects the waveform of the data signal based on the clock signal. It has a waveform observation function that observes the

Specifically, the waveform observing section 4 has a trigger generating section 41 , a sampler 42 and a signal waveform processing section 43 . Based on the clock signal output from the clock recovery circuit 3, the trigger generator 41 generates a strobe signal that is used as a sampling timing for operating the sampler 42. FIG. The sampler 42 performs a switching operation at, for example, several hundred kHz using the strobe signal generated by the trigger generation unit 41 as a sampling timing, and samples the signal under measurement (input data signal) converted into an electrical signal by the O/E 2. . The signal waveform processing unit 43 performs processing for detecting the waveform of the input data signal based on sample data from the sampler 42 .

The error rate measuring unit 4a is an error rate detector that receives the data signal output from the O/E 2 as the signal under measurement and detects the bit error rate of the signal under measurement at the timing of the clock signal output from the clock recovery circuit 3. (Error Detector: ED) function. More specifically, the error rate measurement unit 4a identifies the signal level (High/Low) pattern in the signal under measurement based on the clock timing of the clock signal, and compares the identified identification pattern data with the reference pattern to detect errors. Calculate rate. The error rate measurement unit 4a corresponds to the error rate measurement device of the present invention.

The switching unit 4b switches the connection between the O/E 2 and the waveform observing unit 4 or the error rate measuring unit 4a and the connection between the clock recovery circuit 3 and the waveform observing unit 4 or the error rate measuring unit 4a.

The control unit 5 controls operations related to clock recovery processing in the clock recovery circuit 3, controls operations related to data signal sampling processing and waveform observation operations in the waveform observation unit 4, and performs bit error rate calculation processing in the error rate measurement unit 4a. etc., to control the operation of the measuring apparatus 1 as a whole.

As shown in FIG. 4, the control section 5 includes a CPU 5a and an external interface (I/F) section 5i. For example, the CPU 5a executes a program stored in the storage unit 6 to control the setting control unit 5b, the measurement control unit 5c, the display control unit 5d, the phase correction control unit 5e, the transmission rate detection control unit 5f, the notification control unit Each functional part such as 5g is realized.

The setting control unit 5b performs various setting processes such as setting of simulation parameters for measurement of the DUT 50 (waveform observation, bit error rate measurement).

The measurement control unit 5c performs measurement (observation) of the signal under measurement, such as bit error rate detection processing in the error rate measurement unit 4a and waveform detection processing of the signal under measurement based on the sample data described above in the signal waveform processing unit 43. Controls each part related to

The display control unit 5d controls the waveform of the signal under measurement to be displayed on the display unit 8 based on the detection processing of the waveform of the signal under measurement by the signal waveform processing unit 43, and the bit error rate detection by the error rate measurement unit 4a. Control for displaying the result on the display unit 8 is performed. The display control unit 5d also displays a UI screen on the display unit 8 when a data signal (signal under measurement) is input from the DUT 50 to the measuring apparatus 1 when measuring the signal under measurement (waveform observation, bit error rate measurement). Perform display control for displaying. An example of the UI screen is an input screen for inputting a specified transmission rate in association with the input signal (signal under measurement) from the operation unit 7, for example. The display control unit 5d also performs control to display the transmission rate input using the input screen on the front panel 1b (see FIG. 5) of the apparatus main body 1a of the measuring apparatus 1 as the set transmission rate. Note that the display unit 8 may be a housing different from the main body 1a of the measuring device 1, such as a liquid crystal display.

The phase correction control unit 5e sets a DC input value to the phase shift circuit 3b through the terminal 3b1, and performs control to shift the phase of the clock signal output from the VCO 3a based on the set input DC value. It is something to do. Regarding the method of sweeping the control voltage (DC input value) related to the control of the phase shift in the phase correction control section 5e, the DC input value is sequentially swept with a preset step width until it is determined that the PLL circuit section 3e is locked. There is a method of changing setting, and a method of directly setting the voltage (DC input value) at lock time of the PLL circuit section 3e corresponding to the transmission rate of the signal under measurement by reading it from a phase correction control table (not shown). .

The phase correction control section 5e further has a lock determination function for determining that the PLL circuit section 3e is locked. The lock determination function monitors, for example, whether or not the phase error signal sent by the phase comparator 3c has reached a value free of phase error, and the PLL circuit unit 3e is locked when the value has no phase error. It has a configuration to determine that it is a thing (lock is confirmed). The lock determination function has, for example, a lock count circuit, receives a clock signal output from the VCO 3a as a lock confirmation clock signal, and counts the lock confirmation clock signal within a predetermined period. The functional configuration may be such that it is determined that the lock is established when the count value of the signal matches the expected value, and it is determined that the lock is not established when the count value of the signal does not match. Here, the expected value is the number of clock signals (number within a predetermined period) corresponding to the transmission rate (standard rate) of the signal under measurement. In order to realize the lock determination function, for example, a lock determination control table may be provided in the storage unit 6, and an expected value corresponding to each transmission rate (standard rate) may be registered in advance.

The transmission rate detection control section 5f detects the transmission rate of the input signal under measurement for measurement or waveform observation. The transmission rate detection control section 5f can be constructed by having counting means for counting the actual input signal (signal to be measured) by means of the counting means. Further, the transmission rate detection control section 5f has, for example, a counting circuit (counting means) for counting the clock signal output from the VCO 3a. The transmission rate may be detected based on the count value of the clock signal by the counter circuit when the PLL circuit section 3e is locked.

For example, when measuring a signal under measurement (bit error rate measurement), the notification control unit 5g detects a transmission rate set by a user (hereinafter also referred to as a set rate) and a transmission rate detection control unit 5f. The transmission rate of the measured signal (hereinafter also referred to as the detection rate) is compared, and if the set rate and the detection rate are different, control is performed to notify that measurement is impossible (see FIG. 5). It is a functional part. When observing the waveform of the signal under measurement, the notification control unit 5g cannot observe the waveform if the transmission rate set by the user differs from the transmission rate of the signal under measurement detected by the transmission rate detection control unit 5f. Executes control to inform that effect (see FIG. 5). When the PLL circuit unit 3e locks at a transmission rate (detection rate) different from the set rate, the notification control unit 5g also controls to perform notification (see FIG. 6) to prompt confirmation of the detection rate at which locking is confirmed. It also has functions.

The external I/F unit 5i has an interface function for accessing an external device via the network 10. In this embodiment, the network 10 is connected between the measuring device 1 and an external control device 11 (see FIG. 1). It also provides an interface function for sending and receiving signals via In the present embodiment, the measuring device 1 can be configured to operate according to commands from an external control device 11 via the network 10 in addition to the operation controlled by the control unit 5 of the measuring device 1 itself. The system operation in this case can be realized by providing a control unit (not shown) of the control device 11 with a functional unit equivalent to the control unit 5 .

The storage unit 6 is necessary for the CPU 5a to realize each functional unit such as the setting control unit 5b, the measurement control unit 5c, the display control unit 5d, the phase correction control unit 5e, the transmission rate detection control unit 5f, and the notification control unit 5g. In addition to these programs, the phase correction control unit 5e stores a phase correction control table used for sweep control of the DC input value during clock regeneration processing, a lock determination control table used for lock determination, and the like.

The operation unit 7 is composed of an operation panel such as switches and buttons. The operation panel may have a touch panel function. The operation unit 7 performs measurement of the DUT 50 (signal under measurement) or setting of transmission rate associated with the signal under measurement implemented before waveform observation, instruction to start phase correction control, subsequent measurement of the DUT 50, and start of waveform observation. It is configured to selectively execute various settings necessary for measurement of the DUT 50 and waveform measurement, including setting of various information necessary for performing desired display on the display unit 8, instruction to stop the operation, and the like.

In particular, in the present embodiment, the operation unit 7 is configured to accept an input of the transmission rate from the user in cooperation with the display screen displayed on the display unit 8 and send it to the control unit 5 . ing. Thus, in the control unit 5, the setting control unit 5b can set the input transmission rate in association with the signal under measurement. In this manner, the operation unit 7 constitutes setting means 9 (see FIG. 4) together with the display unit 8, the setting control unit 5b, and the display control unit 5d.

The display unit 8 is composed of a display device such as a liquid crystal panel, and displays various information related to measurement of the DUT 50 and waveform measurement. The display unit 8 displays an input screen constituting the setting means 9 under the control of the display control unit 5d. Note that the display unit 8 may be a housing different from the main body 1a of the measuring device 1, such as a liquid crystal display. The display unit 8 has a display function unit other than the liquid crystal panel. For example, the lock state display unit 1c, the transmission rate display unit 1d, and the It also includes a notification message display section 1e.

The configuration of the display function unit provided on the front panel 1b of the measuring device 1 and the display mode will be described in detail with reference to FIGS. 5 and 6. FIG.

FIG. 5 is a diagram showing the main configuration of the front panel 1b of the measuring device 1 according to the present embodiment, and particularly shows the configuration of the display function unit for notifying the measurement impossible state due to an erroneous setting of the transmission rate. It is a diagram.

A lock state display section 1c and a transmission rate display section 1d are provided on the front panel 1b of the device body 1a of the measurement device 1 as display function sections for notifying a measurement impossible state due to an erroneous setting of the transmission rate. . The lock state display section 1c is a section that displays whether the PLL circuit section 3e of the clock recovery circuit 3 is in the locked or unlocked state. In the present embodiment, the lock state display unit 1c has a display lamp clearly indicating "Unlock", and is configured to transmit the display lamp in the unlock state. The lock state display unit 1c is not limited to this configuration. For example, the lock state display unit 1c has a light emitting element such as a light emitting diode that can be driven to emit light by switching between different colors (for example, red and green). The configuration may be such that they are lit in corresponding colors (for example, green and red) accordingly.

The transmission rate display unit 1d is a functional unit that displays the transmission rate set by the user. The transmission rate is indicated by a number, and the unit is, for example, [GbE/4], [Gbaud], or [Kbaud]. In FIG. 5, the transmission rate display section 1d is composed of a first display section 1d1 and a second display section 1d2. Transmission rate values in units of ``GbE/4'' and ``Gbaud'' are displayed on the first display portion 1d1, and transmission rate values in units of ``Kbaud'' are displayed on the second display portion 1d2. It's becoming In this example, values of "400 GbE/4" and "53.125 Gbaud" are respectively displayed on the first display section 1d1 as examples of set rates, and the same transmission rate of "53 125 000 Kbaud" is displayed on the second display section 1d2. ” is displayed as a value.

For the display function unit configured as shown in FIG. 5, the notification control unit 5g determines that the set rate and the detection rate are different when the lock determination function detects that the PLL circuit unit 3e is in the unlocked state. Then, the lock state display section 1c provided on the front panel 1b of the apparatus main body 1a is controlled so that the display lamp clearly indicating "Unlock" is turned on. At this time, the display control unit 5d causes the transmission rate display unit 1d to display the transmission rate set in advance in association with the signal under measurement by the user prior to measuring the signal under measurement. maintained.

The display mode shown in FIG. 5 is a display mode for notifying a waveform observable state related to an erroneous transmission rate setting. According to this display mode, the user can check the transmission rate set by himself and the fact that the PLL circuit section 3e is not in the locked state from the display contents of the lock state display section 1c and the transmission rate display section 1d on the front panel 1b. and can easily recognize that it is in an unmeasurable state.

The display control unit 5d determines that the PLL circuit unit 3e is in the locked state by the lock determination function of the transmission rate detection control unit 5f, and if the set transmission rate and the detected transmission rate match at that time, the display control unit 5d controls to extinguish the display lamp indicating "Unlock" in the lock state display section 1c. As a result, the user can recognize on the front panel 1b of the device main body 1a of the measuring device 1 that the transmission rate set by him/herself and the settings are correct, that is, that the measurement is possible.

FIG. 6 is a diagram showing the essential configuration of the front panel 1b of the measuring device 1 according to the present embodiment, and in particular, is a diagram showing the configuration of the display function unit for notifying that confirmation of the transmission rate is requested. . As a display function unit for realizing the display form shown in FIG. 6, the front panel 1b of the measuring device 1 is further provided with a notification message display unit 1e in addition to the lock state display unit 1c and the transmission rate display unit 1d. there is

For the display function unit configured as shown in FIG. 6, the display control unit 5d causes the transmission rate display unit 1d to display the transmission rate set in advance by the user in the same manner as the display mode shown in FIG. On the other hand, when the PLL circuit unit 3e locks at a transmission rate different from the set transmission rate (or when lockable), the notification control unit 5g displays the lock state display unit 1c with "Unlock". Control is performed so that the specified display lamp is extinguished, and then a notification message for prompting confirmation of the transmission rate (detection rate) at which locking is confirmed is displayed on the notification message display part 1e. As a specific example of the notification message, the notification control unit 5g includes the detection rate detected by the transmission rate detection control unit 5f (the transmission rate at which the locked state is established), and notifies that the signal of the detection rate is input. Display a message that prompts you to confirm.

FIG. 6 shows a display example of a notification message with the content "Is xx Gbaud rate being input?". Here, "xx Gbaud rate" indicates the detection rate. The user can see the display on the notification message display section 1e on the front panel 1b and can quickly confirm whether or not the detection rate "xx Gbaud rate" is input as the set rate.

Next, the operation of the measuring device 1 having the configuration described above will be described. This measuring apparatus 1 has a table setting mode, a phase correction control mode, a measurement mode and a waveform observation mode. When the table setting mode is set, the UI screen for table setting is displayed on the display unit 8 by the display control unit 5d, and the setting of the phase correction control table, the lock determination control table, etc. can be performed from the operation unit 7. .

When the phase correction control mode is set, first, a UI screen for setting the transmission rate (input rate) of the signal under measurement to be input for measurement or waveform observation is displayed on the display unit 8 by the display control unit 5d. Is displayed. The user selects a desired standard on the UI screen by performing a predetermined selection operation on the operation unit 7, and inputs the transmission rate corresponding to the selected standard in association with the signal under measurement to be input from now on. be able to. The UI screen displayed here is the UI screen that constitutes the setting means 9 (see FIG. 4).

Furthermore, in the phase correction control mode, as described above, after the transmission rate (standard rate) is input in association with the signal under measurement, the user operates, for example, in accordance with the input of the signal under measurement (data signal) from the DUT 50. By performing a predetermined phase correction control start operation in the unit 7, measurement of the signal under measurement or waveform observation processing can be performed.

In the process of measuring the signal under measurement, the clock recovery circuit 3 of the measuring apparatus 1 regenerates a clock signal from the input signal under measurement. 4a. On the other hand, in the waveform observation process, the clock recovery circuit 3 of the measuring apparatus 1 recovers a clock signal from the input signal under measurement, and the clock signal is passed through the switching unit 4b to the waveform observation unit 4 together with the signal under measurement. supplied to

In the clock signal recovery process in the clock recovery circuit 3, in both the measurement process and the waveform observation process, the input of the signal under measurement is received and the sweep control regarding the DC input value is appropriately performed. With this sweep control, the clock recovery circuit 3 can recover a clock signal synchronized (symbol-synchronized) with the input signal under measurement. For symbol synchronization, the data signal input from the DUT 50 in the measurement device 1 is processed by the signal waveform processing unit 43 of the waveform observation unit 4, and the waveform at the moment when the eye pattern is most opened can be displayed on the display unit 8. synchronous state.

Based on the operation procedures in the phase correction control mode, the measurement mode, and the waveform observation mode described above, the measurement/waveform observation processing operation of the measurement apparatus 1 according to the present embodiment will be described below with reference to the flowchart shown in FIG. .

In order to start the measurement or waveform observation processing by the measuring apparatus 1, first, the UI screen (input screen) described above is displayed on the display unit 8. Prior to inputting the signal under measurement, the user inputs the signal under measurement. A process of accepting an input of a transmission rate is performed (step S1).

When the input of the transmission rate is accepted, the display control unit 5d displays the transmission rate on the transmission rate display unit 1d in the display forms shown in FIGS. 5 and 6, for example. Next, when the phase correction control start designation operation from the user is accepted and the signal under measurement (input signal) sent from the DUT 50 is taken in (step S2), the phase correction control unit 5e sets the phase correction value (DC input value ) is performed (step S3). In this sweep control, the phase correction control unit 5e, for example, exhaustively and sequentially sets each phase correction value for the phase shift circuit 3b in the upward or downward direction, and sequentially sets the phase of the clock signal output from the VCO 3a. The phase shift circuit 3b is controlled so as to shift based on the obtained phase correction value and input it to the phase comparator 3c.

While performing sweep control of the phase correction value in step S3, the transmission rate detection control unit 5f counts the clock signal output from the VCO 3a of the clock recovery circuit 3 by the count circuit, and the count value and each transmission rate are A process of detecting the transmission rate of the signal under measurement is performed based on the result of comparison with the number of clocks registered correspondingly (step S4).

While performing the transmission rate detection processing in step S4, the phase correction control unit 5e further performs lock confirmation processing for determining whether or not the PLL circuit unit 3e is locked by the lock determination function (step S5). Here, the phase correction control unit 5e takes in the clock signal output from the VCO 3a as a lock confirmation clock signal, counts it by the lock count circuit, and the count value of the lock confirmation clock signal within a predetermined period reaches the expected value. If they match, it is determined that the lock is established, and if they do not match, it is determined that the lock is not established.

If it is determined that the lock is established (YES in step S5), then the display control unit 5d controls the lock state display unit 1c to display the locked state (step S6).

Subsequently, the notification control unit 5g compares the set rate set by the user and the detection rate detected by the transmission rate detection control unit 5f, and determines whether or not they are different (step S7).

Here, if it is determined that the detected transmission rate and the set transmission rate match (YES in step S7), the phase correction control unit 5e fixes the phase correction value set in the phase shift circuit 3b to the lock voltage, Control is performed so that the clock signal synchronized with the input signal is continuously output from the clock recovery circuit 3 to the error rate measurement section 4a or the waveform observation section 4 (step S8).

After that, the measuring apparatus 1 shifts to the measurement mode or the waveform observation mode by the user's measurement mode setting operation or waveform observation mode setting operation. In the measurement mode, the error rate measurement unit 4a can use the clock signal supplied from the clock recovery circuit 3 to measure the bit error rate of the data signal (step S9). On the other hand, in the waveform observation mode, the waveform observation section 4 uses the clock signal supplied from the clock recovery circuit 3 to observe the waveform of the data signal branched at the preceding stage of the clock recovery circuit 3 (step S9). become executable.

On the other hand, if it is determined in step S5 that the PLL circuit section 3e is not locked (NO in step S5), then the notification control section 5g notifies that measurement is impossible due to an erroneous setting of the transmission rate. Control is performed (step S10). The control for notifying that the measurement is not possible is performed particularly when the measurement mode is set in step S9. More specifically, when the bit error rate measurement mode is set, it notifies that the bit error rate cannot be measured. When the waveform observation mode is set in step S9, for example, control is performed to notify that the waveform observation is not possible (step S10). After executing step S10, the process ends.

In the notification control in step S10, the notification control unit 5g, for example, as shown in FIG. Control. That is, control is performed so that the display lamp indicating Unlock is extinguished. At this time, the display control unit 5d maintains a state in which the transmission rate set in advance by the user in association with the signal under measurement is displayed on the transmission rate display unit 1d prior to measuring the signal under measurement.

If it is determined in step S7 that the detected rate is different from the set rate (NO in step S7), the notification control unit 5g confirms the transmission rate (detected rate) that is different from the set rate but is confirmed to be locked. (step S11), and then the process ends.

In the notification control of step S11, the notification control unit 5g determines that the PLL circuit unit 3e has locked at a transmission rate different from the set transmission rate, and for example, as shown in FIG. For example, the transmission rate is illuminated in green to indicate that the transmission rate is locked, and a notification message is displayed on the notification message display unit 1e to prompt resetting to the transmission rate at which the lock has been confirmed.

In the example of FIG. 6, a notification message with the content "Is xx Gbaud rate being input?" is displayed. Here, "xx Gbaud rate" indicates the detected transmission rate.

In the case of locking at a detection rate different from the set rate, the notification message is displayed in the notification message display unit 1e by highlighting the notification message using at least one of a font of a specific color and blinking. desirable. As an example of highlighting, there is a method of displaying the font color of the notification message in the notification message display portion 1e in a conspicuous color such as red or yellow by the display control portion 5d. In addition to color control, a notification message may also be flashed.

According to the present embodiment, in the series of processing operations shown in FIG. 7, if locking of the PLL circuit unit 3e with respect to the set rate cannot be confirmed, the set mode (measurement mode or waveform observation mode) ), a measurement-impossible state or a waveform-observable state related to an erroneous setting of the transmission rate is reported (step S10, see FIG. 5). Further, when locking occurs at a transmission rate different from the set rate, a notification message prompting confirmation of the detection rate at which locking has been confirmed in the PLL circuit section 3e is notified (step S11, see FIG. 6). .

According to the display form of the notification shown in FIG. 5, the user can determine the transmission rate set by himself and the PLL circuit section 3e from the display contents of the lock state display section 1c and the transmission rate display section 1d on the front panel 1b. It can be seen that the state has not been established, and it becomes possible to easily recognize that the measurement is not possible or the waveform is not observable. As a result, the correct transmission rate can be reset, and the measurement-enabled state or waveform-observable state can be quickly restored.

Further, according to the notification display form shown in FIG. 6, the user sees the notification message in the notification message display section 1e on the front panel 1b, and the detection rate "XX Gbaud rate" is input as the set rate. You can immediately move on to confirming whether or not there is. You can then continue the measurement at "xx Gbaud rate" or immediately proceed to reset the correct transmission rate.

Regarding the measurement/waveform observation processing operation shown in FIG. 7, even if the detection rate differs from the set rate, if the hardware can be locked (steps S5 to S7), the detection rate is displayed. An example of operation is disclosed in which confirmation is prompted, that is, processing is temporarily stopped (see step S11), but the present invention is not limited to this. The detection rate may be automatically switched and displayed on the transmission rate display section 1d, and the measurement processing or waveform observation processing may be continued at the detection rate.

Further, in the above-described embodiment, a configuration example in which the control function for notification in steps S10 and S11 is provided in the control unit 5 of the measurement device 1 is given. It may be configured to be implemented in the device 11 and to perform the phase correction control of the measuring device 1 from the control device 11 via the network 10 .

Further, in the above-described embodiment, the configuration in which the measurement device 1 includes the clock recovery circuit 3 is exemplified, but a configuration in which the clock recovery circuit 3 is arranged outside the measurement device 1 may be employed.

Further, in the above embodiments, examples of processing signals from optical devices have been mainly explained. It can perform clock recovery processing from the input signal, measurement of the input signal, and waveform observation processing.

As described above, the measuring apparatus 1 according to the present embodiment includes the clock recovery circuit 3 that inputs a signal under measurement, reproduces a clock signal synchronized with the signal under measurement, and sets the transmission rate in association with the signal under measurement. the setting means 9, the transmission rate detection control section 5f for detecting the transmission rate of the input signal under measurement, and the case where the transmission rate set by the setting means 9 and the transmission rate detected by the transmission rate detection control section 5f are different , and a notification control unit 5g for notifying that measurement is impossible.

With this configuration, the measuring apparatus 1 according to the present embodiment notifies that the measurement is impossible when the set transmission rate and the actually detected transmission rate are different when measuring the signal under measurement. Therefore, the user can easily notice the cause of the unmeasurable state, and can quickly take measures to return to the measurable state.

In addition, in the measuring apparatus 1 according to the present embodiment, the clock recovery circuit 3 includes a VCO 3a that outputs a clock signal having an oscillation frequency corresponding to an input voltage, and a voltage generator corresponding to a phase difference signal between the signal under measurement and the clock signal. as an input voltage to the VCO 3a. This configuration detects the transmission rate based on the count value of the clock signal when locked.

With this configuration, the measuring apparatus 1 according to the present embodiment can use the existing functions of the clock recovery circuit 3 and realize the transmission rate detection control function with a simple configuration.

In addition, in the measuring apparatus 1 according to the present embodiment, the notification control unit 5g displays a state indicating that the PLL circuit unit 3e is in an unlocked state while the value of the set transmission rate is being displayed. It is a configuration to do.

With this configuration, in the measuring apparatus 1 according to the present embodiment, when the set transmission rate and the detected transmission rate are different and the PLL circuit section 3e does not lock, the user may It is easy to notice that the measurement is impossible at .

In addition, in the measuring apparatus 1 according to the present embodiment, when the PLL circuit unit 3e is locked at a transmission rate different from the set transmission rate, the notification control unit 5g sets a numerical value indicating the detected transmission rate. and display a notification message prompting confirmation of the detected transmission rate.

With this configuration, the measuring apparatus 1 according to the present embodiment prompts confirmation of the transmission rate at which locking is possible even when the set transmission rate and the detected transmission rate are different. It becomes possible to shift to the measurement operation in the state.
can do.

Moreover, in the measuring device 1 according to the present embodiment, the notification control unit 5g has a configuration for highlighting the notification message using at least one of a font of a specific color and blinking.

With this configuration, when the measuring apparatus 1 according to the present embodiment is locked at a transmission rate different from the set transmission rate, the measurement apparatus 1 reliably confirms the transmission rate at which locking becomes possible, and prompts the user to confirm the transmission rate. It is possible to encourage prompt response to

Further, the measuring apparatus 1 according to the present embodiment is a waveform observing apparatus and further includes a waveform observing section 4 that observes the waveform of the signal under measurement using the clock signal reproduced by the clock recovery circuit 3. 9 sets a transmission rate in association with the signal under measurement whose waveform is observed; It has a configuration for notifying that the waveform cannot be observed.

With this configuration, when the waveform observing section 4 observes the waveform of the signal under measurement, the measuring apparatus 1 according to the present embodiment uses the transmission rate set in association with the signal under measurement whose waveform is observed and the transmission rate actually detected. If the rates are different, the fact that waveform observation is not possible is notified, so that the user can easily find out the cause of the waveform observability condition, and a prompt action can be taken to restore the waveform observable condition. .

Further, the measuring apparatus 1 according to the present embodiment is an error rate measuring apparatus, and includes a bit error rate measuring unit 4a for measuring the bit error rate of the signal under measurement using the clock signal reproduced by the clock recovery circuit 3. In addition, the setting means 9 sets the transmission rate in association with the signal under measurement whose bit error rate is to be measured, and the transmission rate set by the setting means 9 differs from the transmission rate detected by the transmission rate detection control section 5f. In this case, the notification control unit 5g has a configuration for notifying that the bit error rate cannot be measured.

With this configuration, when the bit error rate measuring unit 4a measures the bit error rate of the signal under measurement, the measuring apparatus 1 according to the present embodiment has a transmission rate set in association with the signal under measurement whose bit error rate is to be measured, If the actually detected transmission rate is different, the fact that the bit error rate cannot be measured is notified, so that the user can easily find out the cause of the bit error rate unmeasurable state. It is possible to respond quickly to return to.

In addition, the measurement method according to the present embodiment includes a clock recovery circuit 3 that inputs a signal under measurement and reproduces a clock signal synchronized with the signal under measurement, and reproduces the signal under measurement using the reproduced clock signal. A measurement method for measuring, comprising a setting step S1 for setting a transmission rate in association with a signal under measurement, a transmission rate detection step S4 for detecting the transmission rate of the input signal under measurement, and the transmission set in the setting step S1 and a notification step S10 for notifying that measurement is impossible when the rate and the transmission rate detected in the transmission rate detection step S4 are different.

With this configuration, the measurement method according to the present embodiment notifies that measurement is impossible when the set transmission rate differs from the actually detected transmission rate when measuring the signal under measurement. , the user can easily notice the cause of the waveform observable state, and can quickly take measures to restore the measurable state.

(Second embodiment)
FIG. 8 is a block diagram showing the configuration of the clock recovery circuit 3A of the measuring apparatus 1A according to the second embodiment of the present invention, and FIG. 9 is a block diagram showing the functional configuration of the control section 5A of the measuring apparatus 1A. . 9 and 10, the same reference numerals are given to the same components as those of the measuring apparatus 1 according to the first embodiment.

As shown in FIGS. 8 and 9, in the measuring device 1A according to the present embodiment, the clock recovery circuit 3A includes an O/E 2A. The O/E 2A converts the signal under test (optical signal) sent out from the DUT 50 into an electric signal and sends it to the phase comparator 3c of the clock recovery circuit 3A, and also corresponds to the optical power of the signal under test (optical power). It has the function of outputting a signal (electrical signal).

A signal path is provided between the clock recovery circuit 3A and the controller 5A for inputting a signal corresponding to the optical power output from the O/E 2 to the amplitude detection controller 5h of the controller 5A. The amplitude detection control section 5h has an amplitude detection function of detecting the amplitude of the signal under measurement based on the above-described signal input from the O/E 2. FIG.

The measuring apparatus 1A according to the present embodiment has an amplitude detection control section 5h, and the notification control section 5g1 detects that the measurement is impossible when the amplitude of the signal under measurement detected by the amplitude detection control section 5h is smaller than a preset level. It has a control function to notify that The notification control section 5g1 has the control function of the notification control section 5g of the measuring apparatus 1 according to the first embodiment, and an amplitude level-based notification control function added thereto. The configuration other than the measurement impossibility notification control function based on the amplitude level of the signal under measurement is the same as that of the measurement apparatus 1 according to the first embodiment.

A waveform observing operation of the measuring apparatus 1A according to this embodiment will be described with reference to FIG. In FIG. 10, processing steps other than steps S21 to S24 are processing steps common to the measuring apparatus 1 according to the first embodiment. Here, redundant description of common processing steps will be omitted, and the notification control operation of the waveform observable state based on insufficient amplitude of the signal under measurement will be described, mainly focusing on steps S21 to S24.

In order to start the waveform observation processing in the measuring apparatus 1A, first, a UI screen (input screen) is displayed on the display unit 8. Prior to inputting the signal under measurement, the user can input the transmission rate related to the signal under measurement. (step S1).

When the input of the transmission rate is accepted, the display control unit 5d displays the transmission rate on the transmission rate display unit 1d in the display forms shown in FIGS. 5 and 6, for example. Next, when the phase correction control start designation operation from the user is accepted and the signal under measurement (input signal) sent from the DUT 50 is taken in (step S2), the phase correction control unit 5e sets the phase correction value (DC input value ) is performed (step S3). After that, the measurement apparatus 1A executes the processing steps after step S3. However, in FIG. 10, illustration of processing steps S4 to S11 is omitted.

Further, in the measuring apparatus 1A, as a processing step unique to this embodiment, after starting to take in the signal under measurement in step S2, notification control of a waveform observable state due to insufficient amplitude of the signal under measurement is executed.

In this notification control, first, in the control section 5A, the signal output from the O/E 2 (the signal indicating the optical power of the signal under measurement) is input to the amplitude detection control section 5h (step S21). Next, the amplitude detection control section 5h detects the amplitude of the signal under measurement based on the signal input from the O/E 2 (step S22).

Subsequently, the notification control unit 5g1 compares the amplitude of the signal under measurement detected in step S22 with the amplitude set in advance as a threshold value (amplitude level required for normal waveform measurement), and determines whether the detected amplitude is It is determined whether or not it is equal to or greater than the threshold (step S23). If it is determined that the detected amplitude is greater than or equal to the threshold value (YES in step S23), the control from step S3 onwards is continued.

On the other hand, if it is determined that the detected amplitude is smaller than the threshold value (NO in step S23), the notification control unit 5g1 executes control to notify a measurement impossible state due to insufficient amplitude of the signal under measurement (step S24), after which all control (phase correction control, measurement, or waveform observation control) operations are terminated. As a specific example, a threshold value of -10 dBm (power) may be set, and notification may be made when the amplitude level is smaller than this threshold value. Note that the control of the notification that the measurement is impossible due to insufficient amplitude of the signal under measurement in step S24 is performed particularly when the measurement mode is set. When the waveform observation mode is set, for example, control is performed to notify that the waveform cannot be observed due to insufficient amplitude of the signal under measurement.

In the notification control in step S24, the notification control unit 5g1 displays, for example, "Measurement is not possible due to insufficient amplitude of the signal under measurement." There is a method of displaying a notification message to the effect that waveform observation is impossible due to the fact that the waveform is abnormal). Needless to say, such a notification message may be displayed in another display area of the display section 8. FIG.

By viewing the notification message displayed in step S24, the user can immediately move on to identifying the cause, and can shorten the time required to identify the cause and restore correct measurement operation.

As described above, the measuring apparatus 1A according to the present embodiment further includes the amplitude detection control section 5h for detecting the amplitude of the input signal under measurement, and the notification control section 5g1 detects the amplitude of the signal under measurement. is smaller than the amplitude value set corresponding to , it is configured to notify (in the case of measurement) that the measurement is impossible due to the amplitude abnormality of the signal under measurement. Here, when the waveform of the signal under measurement is being observed by the waveform observing section 4, it may be configured to notify that the waveform of the signal under measurement cannot be observed due to an amplitude abnormality.

With this configuration, the measuring apparatus 1A according to the present embodiment can quickly eliminate the measurement impossible state (or waveform observable state) due to the small amplitude of the signal under measurement. , erroneous measurement results and waveform observation results can be avoided.

In addition, in the measuring apparatus 1A according to the present embodiment, the amplitude detection control section 5h converts the signal under measurement sent as an optical signal from the DUT 50 into an electrical signal and outputs the electrical signal, while at the same time corresponding to the optical power of the optical signal. It has an O/E 2A that outputs a signal, and an amplitude detection control section 5h that detects the amplitude of the signal under measurement based on the electrical signal corresponding to the optical power.

With this configuration, the measuring apparatus 1A according to the present embodiment can realize the amplitude detection function with a simple configuration using the optical power detection function of the existing O/2A.

The measurement method according to the present embodiment further includes an amplitude detection step S22 for detecting the amplitude of the input signal under measurement. If the amplitude value is smaller than the set amplitude value, there is a step S24 of further notifying (at the time of measurement) that the signal under measurement cannot be measured due to amplitude abnormality. Here, when the waveform observation of the signal under measurement is being performed by the waveform observing section 4, it may be notified that the waveform observation of the signal under measurement is impossible due to an amplitude abnormality.

With this configuration, the measurement method according to the present embodiment can quickly eliminate the measurement-impossible state or the waveform-observable state due to the small amplitude of the signal-under-measurement. It is also possible to avoid obtaining measurement results and waveform observation results.

INDUSTRIAL APPLICABILITY As described above, the measuring device and the measuring method according to the present invention enable the user to easily identify the cause of the inability to measure (waveform observation, bit error rate measurement), and measure (waveform observation, bit error rate measurement). This has the effect of being able to quickly return to a state where measurement is possible. It is useful for measuring devices and measuring methods in general, which have a function of informing that rate measurement is impossible.

1, 1A measuring device 2, 2A photoelectric converter (O/E) (photoelectric conversion means, amplitude detection means)
3, 3A clock recovery circuit (clock recovery means)
3a voltage controlled oscillator (VCO)
3b phase shift circuit 3c phase detector (Phase Detector: PD) (phase comparison means)
3e PLL (Phase-Locked Loop) circuit section 4 waveform observation section (waveform observation means)
4a error rate measurement unit (error rate measurement device)
5, 5A control section 5b setting control section (setting means)
5f transmission rate detection control section (transmission rate detection means)
5g, 5g1 Notification control unit (notification means)
5h amplitude detection control unit (amplitude detection means, amplitude detection control means)
7 Operation unit (setting means)
8 display unit (setting means)
9 setting means 10 signal generator (Pulse Pattern Generator: PPG)
50 Device under test (DUT)

Claims (10)

clock recovery means (3) for receiving a signal under measurement and recovering a clock signal synchronized with the signal under measurement;
setting means (9) for setting a transmission rate in association with the signal under measurement;
transmission rate detection means (5f) for detecting the transmission rate of the input signal under measurement;
notification means (5g) for notifying that measurement is impossible when the transmission rate set by the setting means and the transmission rate detected by the transmission rate detection means are different;
and
The clock reproducing means includes a voltage controlled oscillator (3a) for outputting the clock signal having an oscillation frequency corresponding to an input voltage, and a voltage corresponding to a phase difference signal between the signal under measurement and the clock signal. as
The transmission rate detection means detects the transmission rate based on the count value of the clock signal when the PLL circuit unit is locked by phase shift control of the clock signal input to the phase comparison means,
The measurement apparatus, wherein the notifying means displays a state indicating that the PLL circuit section is in an unlocked state while the value of the set transmission rate is being displayed. The notifying means includes a numerical value indicating the detected transmission rate and confirms the detected transmission rate when the PLL circuit unit is locked at a transmission rate different from the set transmission rate. 2. The measuring device according to claim 1, wherein a prompting notification message is displayed. 3. The measuring apparatus according to claim 2, wherein the notification means highlights the notification message using at least one of a specific color font and blinking drive. Amplitude detection means (2A, 5h) for detecting the amplitude of the input signal under measurement ;
The notification means further includes a notification control unit (5g1) to which a notification control function based on the amplitude is added ,
When the amplitude of the signal under measurement is smaller than an amplitude value set corresponding to the signal under measurement, the notification control unit notifies that the measurement is impossible due to the abnormal amplitude of the signal under measurement. 4. The measuring device according to any one of claims 1 to 3, characterized in that: The amplitude detection means is
Photoelectric conversion means (2A) for converting the signal under measurement transmitted as an optical signal into an electric signal and outputting the same, while outputting a signal corresponding to the optical power of the optical signal;
Amplitude detection control means (5h) for detecting the amplitude of the signal under measurement based on the electrical signal corresponding to the optical power;
5. The measuring device according to claim 4, comprising: The measurement device is a waveform observation device,
further comprising waveform observation means (4) for observing the waveform of the signal under measurement using the clock signal reproduced by the clock reproduction means;
The setting means sets a transmission rate in association with the signal under measurement whose waveform is observed,
4. When the transmission rate set by said setting means is different from the transmission rate detected by said transmission rate detection means , said notification means notifies that waveform observation is impossible. The measurement device according to any one of . The measurement device is an error rate measurement device,
further comprising a bit error rate measurement unit (4a) for measuring the bit error rate of the signal under measurement using the clock signal reproduced by the clock reproduction means;
The setting means sets a transmission rate in association with the signal under measurement whose bit error rate is to be measured,
2. When the transmission rate set by said setting means is different from the transmission rate detected by said transmission rate detection means, said notification means notifies that bit error rate measurement is impossible. 4. The measuring device according to any one of items 1 to 3 . A clock reproducing means (3) for receiving a signal under measurement and reproducing a clock signal synchronized with the signal under measurement is provided, and the clock reproducing means outputs the clock signal having an oscillation frequency corresponding to the input voltage. A PLL circuit section ( 3e), wherein the signal under measurement is measured using the clock signal output by the voltage-controlled oscillator,
a setting step (S1) of setting a transmission rate in association with the signal under measurement;
a transmission rate detection step (S4) for detecting the transmission rate of the input signal under measurement;
a notification step (S10) of notifying that measurement is impossible when the transmission rate set in the setting step and the transmission rate detected in the transmission rate detection step are different;
including
the transmission rate detecting step detects the transmission rate based on the count value of the clock signal when the PLL circuit unit is locked by phase shift control of the clock signal input to the phase comparison means;
The notification step displays a state indicating that the PLL circuit section is in an unlocked state while the value of the set transmission rate is being displayed;
further comprising an amplitude detection step (S22) for detecting the amplitude of the input signal under measurement;
In the reporting step, when the amplitude of the signal under measurement is smaller than an amplitude value set corresponding to the signal under measurement, the reporting step further reports that the measurement is impossible due to the abnormal amplitude of the signal under measurement ( S24) A measuring method characterized by: The notifying step includes a numerical value indicating the detected transmission rate when the PLL circuit unit is locked at a transmission rate different from the set transmission rate, and confirms the detected transmission rate. 9. The measuring method according to claim 8, wherein a prompting notification message is displayed. 10. The measuring method according to claim 9, wherein the notification step highlights the notification message using at least one of a specific color font and blinking drive.

Images