JP6890625B2 - Error measuring instrument and method for measuring response time using it - Google Patents

Description

In the present invention, in measuring the error rate of the object to be measured, an error measuring device for measuring the response time when a parameter value change instruction is given during link training for managing the state of the link and an error measuring device thereof are used. Regarding the method of measuring the response time.

In recent years, various digital communication devices are required to have a larger capacity transmission capacity due to an increase in the number of users and the spread of multimedia communication, and one of the indexes for quality evaluation of digital signals in these digital communication devices. As a known bit error rate, which is defined as a comparison between the number of received data in which a code error has occurred and the total number of received data.

Therefore, when a desired digital communication device is used as an object to be measured and the bit error rate in the object to be measured is measured, for example, an error rate measuring device as disclosed in Patent Document 1 or Patent Document 2 below may be used. Used. In this type of error rate measuring device, in order to measure how much the measured object can tolerate electrical stress, an electrical stress signal of a known pattern is applied to the measured object as a test signal from a pattern generator. This test signal is looped back inside or outside the object to be measured and received, and by comparing the received signal with the test signal, the jitter tolerance measurement is performed to measure the presence or absence of an error with respect to the applied amount of the test signal. ..

By the way, in the above-mentioned error measuring instrument, when measuring the error rate of the object to be measured, the response time when a parameter value change instruction is given during link training for managing the link state may be measured. is there. For example, in the case of PCI Express (hereinafter abbreviated as PCIe), one of the compliance test items is a response time test (Tx Link Evaluation Response Time test). This test is performed by the procedure (1) to (3) shown below.

(1) Start link training to put the object to be measured (DUT) in a loopback state.
(2) During the link training, the measuring instrument instructs to change the parameter value (for example, the enhancement value) of the object to be measured.
(3) The response time from when the parameter value change is instructed until the object to be measured actually changes to the instructed parameter value is measured.

Here, FIG. 3 shows a general connection configuration when the above-mentioned response time test is performed. In this connection configuration, the pattern generator 22 of the error measuring device 21 as a measuring instrument and the waveform measuring device 23 are connected by a cable, and a trigger is input from the pattern generator 22 to the waveform measuring device 23 via the cable. .. Further, the pattern generator 22 of the error measuring device 21 is connected to the object W to be measured and the waveform measuring device 23 with a cable via a divider 24, respectively. Further, the error detector 25 of the error measuring device 21 is connected to the object W to be measured and the waveform measuring device 23 with a cable via the divider 26, respectively.

Then, when the response time is measured by the connection configuration of FIG. 3, the data transmitted by the pattern generator 22 of the error measuring device 21 (including the data instructing the change of the parameter value) is branched into two by the divider 24. To do. One of the data branched by the divider 24 is input to the waveform measuring device 23, and the other is input to the object W to be measured. Then, the data transmitted by the object W to be measured (including the data in which the parameter value is changed) is branched into two by the divider 26. The data branched by the divider 26 is input to the error detector 25 of the error measuring device 21 for link training with the object W to be measured, and to the waveform measuring device 23 for observing the change of the parameter value. Entered. Then, by decoding the waveform of the data acquired by the waveform measuring device 23, the response time from when the object to be measured W receives the instruction to change the parameter value to when the parameter value is actually changed is measured.

Japanese Unexamined Patent Publication No. 2007-274474

However, in the conventional connection configuration described above, the waveform is deteriorated because the data transmitted by the object W to be measured is branched by the dividers 24 and 26, respectively, and even if the waveform is acquired by the waveform measuring device 23, a decoding error occurs. In some cases, it occurs and the response time cannot be measured normally. As a countermeasure, to prepare a more expensive component (divider or cable), or to widen the eye opening of the waveform by complicated calculation with CTLE (Continuos Time Liner Equalizer) or DFE (Decision Feedback Equalizer) of the waveform measuring device 23. Is required to be set.

Further, in order to branch the data, it is necessary to connect a cable to the transmitting side and the receiving side via dividers 24 and 26, respectively. At that time, since the data is transmitted differentially, the number of dividers 24 and 26 and the number of cables increase by that amount, which is very complicated, requires time and effort for connection, and takes time for measurement. There is a problem that it is costly because an expensive component (corrugation measuring device 23, dividers 24, 26, cable) is also required.

Moreover, in order to measure the response time more accurately, it is necessary to make the lengths of the cables uniform so that there is no time difference. Specifically, on the transmitting side, it is necessary to make the lengths of the cable connecting the waveform measuring device 23 and the divider 24 and the cable connecting the divider 24 and the object W to be measured uniform. Further, on the receiving side, it is necessary to make the lengths of the cable connecting between the waveform measuring device 23 and the divider 26 and the cable connecting between the error detector 25 and the divider 26 uniform.

Therefore, the present invention has been made in view of the above problems, and provides an error measuring device capable of performing measurement with a simple connection configuration without using a waveform measuring device, and a method for measuring a response time using the error measuring device. It is intended to be provided.

In order to achieve the above object, the error measuring instrument according to claim 1 of the present invention changes the parameter value during the link training for managing the state of the link in measuring the error rate of the object W to be measured. An error measuring instrument 1 that measures the response time when instructed.
The parameter value is a set value by the preset value corresponding to the amplitude of each power strips,
When the parameter value change instruction is given, a training pattern including a trigger and the parameter value change instruction is generated, and a pattern generation that generates a test signal of a known pattern in a state where the object to be measured transitions to loopback. Vessel 2 and
Starting from the trigger input from the pattern generator, the time when the pattern generator transmits data including the parameter value change instruction to the object to be measured and the parameter value are changed according to the parameter value change instruction. It is provided with an error detector 3 that measures the response time from the difference from the time when data is received from the object to be measured.
The error detector includes a link state management unit 13a for instructing the pattern generator of the training pattern to be generated next for the pattern generator as a training pattern according to the current training sequence of the object to be measured. The error rate is compared between the test signal generated by the pattern generator in the state where the object to be measured is transitioning to loopback and the pattern signal input from the object to be measured in connection with the input of the test signal. Equipped with an error detection unit 13b for detecting
The pattern generator is characterized in that it generates a training pattern including a transition control packet for transitioning the link state of the object to be measured to loopback based on a training sequence instructed by the link state management unit. To do.
The error measuring instrument according to claim 2 of the present invention is the error measuring instrument according to claim 1.
It is characterized by including a display unit 14 that displays a measurement result including the measured response time and the detected error rate.
The error measuring instrument according to claim 3 of the present invention is the error measuring instrument according to claim 1 or 2.
The trigger is generated when a training pattern including an instruction to change the parameter value is generated, and is input to the error detector 3 via internal wiring.

The method for measuring the response time using the error measuring device according to claim 4 of the present invention is the method for measuring the response time using the error measuring device 1 according to claim 1.
The parameter value is a set value by the preset value corresponding to the amplitude of each power strips,
A step of generating a training pattern including a trigger and an instruction to change the parameter value from the pattern generator 2 when the parameter change instruction is given, and a step of generating the training pattern.
As a training pattern according to the current training sequence of the object to be measured, a step of instructing the pattern generator from the link state management unit 13a on a training pattern to be generated next to the pattern generator.
Based on the training sequence instructed by the link state management unit, a step of generating a training pattern including a transition control packet for transitioning the link state of the object to be measured to loopback from the pattern generator, and
From the time when the data including the parameter value change instruction is transmitted to the measured object from the trigger input from the pattern generator and the measured object whose parameter value is changed according to the parameter value change instruction. The step in which the error detector 3 measures the response time from the difference from the time when the data is received, and
A step of generating a test signal of a known pattern from the pattern generator in a state where the object to be measured transitions to loopback, and a step of generating a test signal of a known pattern.
The test signal generated by the pattern generator in a state where the object to be measured is transitioning to loopback and the pattern signal input from the object to be measured in connection with the input of the test signal are transmitted to the error detection unit 13b. It is characterized by including a step of detecting an error rate by comparing with each other.
The method for measuring the response time using the error measuring device according to claim 5 of the present invention is the method for measuring the response time according to claim 4.
It is characterized by including a step of displaying a measurement result including the measured response time and the detected error rate on the display unit 14.
The method for measuring the response time using the error measuring device according to claim 6 of the present invention is the method for measuring the response time according to claim 4 or 5.
It is characterized by including a step of generating the trigger when a training pattern including a change instruction of the parameter value is generated and inputting the generated trigger to the error detector 3 via internal wiring.

According to the present invention, as compared with the conventional connection configuration, a very complicated and time-consuming work is not required, and the response time can be measured at low cost by a simple configuration without using an expensive component. it can.

It is a block diagram which shows the outline of the connection structure of the error measuring instrument which concerns on this invention, and the object to be measured. It is a flowchart which shows the procedure of the method of measuring the response time using the error measuring instrument which concerns on this invention. It is a general connection diagram for measuring a response time.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the attached drawings.

In the present invention, for example, a device conforming to the PCIe standard equipped with LTSSM (Link Training and Status State Machine), which is a link state management mechanism for managing the link state, as the link state management unit Wa, is used as the object W to measure the error rate. It relates to an error measuring instrument for measurement.

As shown in FIG. 1, in measuring the error rate of the object W to be measured, the error measuring instrument 1 gives an instruction to change the parameter value to the object W to be measured during the link training for managing the state of the link. It has a function of measuring the response time from the time when the parameter value is actually changed to the instructed parameter value, and is roughly configured with a pattern generator 2 and an error detector 3.

The pattern generator 2 generates data based on, for example, a training pattern based on a PCIe training sequence or a known pattern, and includes a pattern generation unit 11 and a trigger generation unit 12.

The pattern generation unit 11 is a training pattern based on a training sequence required for the error detector 3 to grasp the current link state of the object W to be measured by an instruction from the link state management unit 13a described later of the error detector 3. Occurs. This training pattern includes data instructing the object W to change the parameter value.

The parameter value is a measured value or a set value, the measured value has an error count, for example, and the set value has a preset value corresponding to, for example, the amplitude for each tap (emphasis value of preshoot and de-emphasis).

The pattern generation unit 11 is a transition for transitioning the link state of the link state management unit Wa of the object W to loopback based on the training sequence instructed from the link state management unit 13a described later of the error detector 3. Generates a training pattern that includes control packets (ordered sets of physical layer packets defined by PCIe).

The pattern generation unit 11 uses PRBS (pseudo-random bit sequence) as a known pattern to be input to the object W to be measured when the error rate of the object W to be measured is measured in a state where the object W to be measured has transitioned to loopback. Generates a pattern signal (test signal) based on a pattern or an arbitrary programmable pattern.

The trigger generation unit 12 generates a trigger as a timing signal. This trigger is generated when the pattern generation unit 11 generates a training pattern including the data of the parameter value change instruction, and is input to the measurement unit 13 of the error detector 3 via an external cable or internal wiring.

The error detector 3 detects an error in which data from the object W to be measured is received, and includes a measuring unit 13, a storage unit 14, and a display unit 15.

In the measurement unit 13, a trigger is input from the trigger generation unit 12 of the pattern generator 2, and the parameter value actually instructed after the parameter value change instruction is given to the object W to be measured during the link training. It has a function of measuring the response time until the change, and includes a link state management unit 13a and an error detection unit 13b.

The measurement unit 13 starts from the trigger input from the trigger generation unit 12 of the pattern generator 2, and the pattern generation unit 11 of the pattern generator 2 transmits a parameter value change instruction to the object W to be measured ( The parameter value change instruction transmission time) is measured, and the measured time is stored in the storage unit 14 as log information.

The measuring unit 13 measures the time (data reception time) when data is actually received from the object W whose parameter value is actually changed according to the parameter value change instruction from the pattern generator 2, and the above-mentioned parameter value change instruction. The response time from the transmission time to the data reception time is measured, and the measured data reception time and response time are stored in the storage unit 14 as log information.

The link state management unit 13a has the same or equivalent mechanism as the link state management unit Wa mounted on the object W to be inspected, and operates according to the standard (for example, PCIe) used.

The link state management unit 13a can recognize the current link state of the link state management unit Wa of the object W by the training pattern communicated with the object W, for example, the LTSSM value and the link speed. , Presence / absence of loopback, LTSSM transition pattern, lane number for identifying lane, link number, generation time and number of occurrences of pattern signal, emphasis amount, adjustment value of equalizer on the receiving side, and various other information are obtained.

In the communication between the error measuring device 1 and the measured object W, the link state management unit 13a transmits a training pattern for grasping the current link state of the measured object W from the pattern generator 2. The current link state of the object W is managed by the training pattern received from the object W, and the pattern generator 2 is next generated as a training pattern according to the current training sequence of the object W. The training pattern to be output is instructed to the pattern generator 2.

The error detection unit 13b is input from the test object W in connection with the input of the test signal of the known pattern generated by the pattern generation unit 11 and the test signal in the state where the object W to be measured is transitioning to the loopback. The error rate is detected by comparing with the pattern signal.

The storage unit 14 stores the parameter value change instruction transmission time, data reception time, and response time measured by the measurement unit 13 as log information, as well as the error rate detected by the error detection unit 13b and various setting information related to error measurement. It stores various information including the LTSSM value and the link speed managed by the link state management unit 13a.

The display unit 15 is composed of a display such as a liquid crystal display, and includes a response time measured by the measurement unit 13 (including a response time stored in the storage unit 14), an error rate detected by the error detection unit 13b, and the like. As a result, various setting screens related to error measurement are displayed.

Next, a method of measuring the response time using the error measuring device 1 configured as described above will be described with reference to FIG. Here, in the case of measuring the response time from the instruction to change the parameter value to the object W to be changed to the actually instructed parameter value during the link training for managing the link state. Will be described as an example.

The pattern generator 2 generates a training pattern including data instructing the object W to change the parameter value based on the training sequence of PCIe according to the instruction from the link state management unit 13a of the error detector 3. 11 is generated, and the trigger generation unit 12 generates a trigger (ST1). This trigger is input to the measurement unit 13 of the error detector 3.

The measurement unit 13 measures the time (parameter value change instruction transmission time) at which the pattern generation unit 11 of the pattern generator 2 transmits the parameter value change instruction to the object W to be measured, starting from the input trigger. , The measured time is stored in the storage unit 14 (ST2).

When the object W to be measured receives an instruction to change the parameter value from the pattern generator 2, the object W changes the corresponding parameter value according to the received instruction (ST3).

Then, when the measuring unit 13 of the error detector 3 receives the data from the object W whose parameter value has been changed in response to the instruction to change the parameter value, the parameter value is actually changed according to the instruction to change the parameter value. The time when the data is received from the object W to be measured (data reception time) is measured, and the measured time is stored in the storage unit 14 (ST4).

Then, the measurement unit 13 of the error detector 3 measures the response time from the above-mentioned parameter value change instruction transmission time to the data reception time (ST5), stores the measured response time in the storage unit 14, and displays the unit. The measurement result is displayed on the display screen of 15 (ST6).

By the way, in the above-described embodiment, PCIe has been described as an example as a standard, but the response time when the measurement object W is instructed to change the parameter value during the link training with the measurement object W. If it is a standard that requires the measurement of, the standard is not limited to PCIe.

As described above, according to the present embodiment, an expensive component (waveform measuring device 23, dividers 24, 25, cable) as shown in the connection configuration of FIG. 3 can be prepared, or CTLE or DFE in the waveform measuring device 23 can be prepared. There is no need to make settings for complicated calculations such as.

Moreover, it eliminates the need for extremely complicated and time-consuming work such as connecting a divider 24 for branching the waveform and a cable, and it is possible to inexpensively measure the response time with a simple configuration without using an expensive component. Can be done.

Although the best mode of the error measuring device according to the present invention and the method for measuring the response time using the same is described above, the present invention is not limited by the description and the drawings in this form. That is, it goes without saying that all other forms, examples, operational techniques, and the like made by those skilled in the art based on this form are included in the scope of the present invention.

1 Error measuring device 2 Pattern generator 3 Error detector 11 Pattern generating part 12 Trigger generating part 13 Measuring part 13a Link state management part (LTSSM)
13b Error detection unit 14 Storage unit 15 Display unit 21 Error measuring device 22 Pattern generator 23 Waveform measuring device 24, 26 Divider 25 Error detector W Measured object (DUT)
Wa Link State Management Department (LTSSM)

Claims (6)

An error measuring instrument (1) that measures the response time when a parameter value change instruction is given during link training for managing the link state when measuring the error rate of the object to be measured (W). ,
The parameter value is a set value by the preset value corresponding to the amplitude of each power strips,
When the parameter value change instruction is given, a training pattern including a trigger and the parameter value change instruction is generated, and a pattern generation that generates a test signal of a known pattern in a state where the object to be measured transitions to loopback. Vessel (2) and
Starting from the trigger input from the pattern generator, the time when the pattern generator transmits data including the parameter value change instruction to the object to be measured and the parameter value are changed according to the parameter value change instruction. It is provided with an error detector (3) that measures the response time from the difference from the time when data is received from the object to be measured.
The error detector is a link state management unit (13a) that instructs the pattern generator of the training pattern to be generated next to the pattern generator as a training pattern according to the current training sequence of the object to be measured. And, the test signal generated by the pattern generator in the state where the object to be measured is transitioning to loopback is compared with the pattern signal input from the object to be measured in connection with the input of the test signal. It is equipped with an error detection unit (13b) that detects the error rate.
The pattern generator is characterized in that it generates a training pattern including a transition control packet for transitioning the link state of the object to be measured to loopback based on a training sequence instructed by the link state management unit. Error measuring instrument. The error measuring instrument according to claim 1, further comprising a display unit (14) for displaying a measurement result including the measured response time and the detected error rate. The trigger according to claim 1 or 2, wherein the trigger is generated when a training pattern including an instruction to change the parameter value is generated, and is input to the error detector (3) via the internal wiring. Error measuring instrument. A method for measuring a response time using the error measuring device (1) of claim 1.
The parameter value is a set value by the preset value corresponding to the amplitude of each power strips,
A step of generating a training pattern including a trigger and a parameter value change instruction from the pattern generator (2) when the parameter change instruction is given, and a step of generating the training pattern including the parameter value change instruction.
As a training pattern according to the current training sequence of the object to be measured, a step of instructing the pattern generator from the link state management unit (13a) on a training pattern to be generated next to the pattern generator.
Based on the training sequence instructed by the link state management unit, a step of generating a training pattern including a transition control packet for transitioning the link state of the object to be measured to loopback from the pattern generator, and
From the time when the data including the parameter value change instruction is transmitted to the measured object from the trigger input from the pattern generator and the measured object whose parameter value is changed according to the parameter value change instruction. The step in which the error detector (3) measures the response time from the difference from the time when the data is received, and
A step of generating a test signal of a known pattern from the pattern generator in a state where the object to be measured transitions to loopback, and a step of generating a test signal of a known pattern.
The error detection unit (13b) detects a test signal generated by the pattern generator in a state where the object to be measured has transitioned to loopback, and a pattern signal input from the object to be measured in connection with the input of the test signal. A method for measuring a response time using an error measuring instrument, which comprises a step of detecting an error rate by comparing with). The method for measuring a response time using an error measuring device according to claim 4, further comprising a step of displaying the measured response time and the measurement result including the detected error rate on the display unit (14). A claim comprising a step of generating the trigger when a training pattern including an instruction to change the parameter value is generated, and inputting the generated trigger to the error detector (3) via internal wiring. A method for measuring response time using the error measuring device according to 4 or 5.

Images