Error tolerance evaluation device

Abstract

To provide a signal generation device which can easily change a frequency and a jitter amount of a period jitter when adding jitter to a prescribed signal such as a video signal.SOLUTION: A video signal transmission circuit 10 of a signal generation device 1 transmits a video signal, and an induction signal transmission circuit 11 generates and transmits a periodical induction signal on which a frequency f(i) is reflected. A jitter characteristic control circuit 12 designates an element number i so as to generate desired jitter J(i) and specifies the frequency f(i) of the induction signal and a coupling line 21-i in the coupling lines 21-1 to 21-N in a transmission line 13. The transmission line 13 adds the jitter J(i) according to a parameter of a wiring interval sV(i) or the like to the video signal with cross talk to the video signal from the induction signal following capacitive coupling and inductive coupling by transmitting the video signal and induction signal via the coupling line 21-i.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a signal generating device for generating a signal to which jitter has been added. An error tolerance evaluation apparatus that evaluates error tolerance using Regarding. [Background technology]

[0002] Conventionally, when transmitting uncompressed 4K or 8K ultra-high definition television signals between professional video devices, various interfaces have been used. For example, a serial digital interface (SDI) such as 12G-SDI is used, which transmits uncompressed digital video and audio via a BNC cable and a coaxial cable (see, for example, Non-Patent Document 1).

[0003] Furthermore, Ultrahigh-definition Signal / Data Interface (hereinafter referred to as "U-SDI") is used for transmitting video signals compatible with 8K resolution, RGB444, high frame rate, wide color gamut, and 12-bit gradation (see, for example, Patent Document 1 and Non-Patent Document 2). The transmission rate of these interfaces exceeds 10 Gbps.

[0004] Generally, in video production equipment such as professional cameras, switchers, and converters that support SDI, electrical differential signals are used for signal transmission between the connectors on the equipment housing and signal processing components such as FPGAs (Field Programmable Gate Arrays).

[0005] Similarly, in video production equipment that supports U-SDI, electrical differential signals are used for signal transmission between signal processing components such as O / E (optical / electrical converters), E / O (electrical / optical converters), and FPGAs.

[0006] In circuit boards equipped with signal processing components, electrical differential signals are affected by factors such as wiring loss due to dielectrics, ripples from power regulators, and simultaneous switching noise, which causes jitter to occur inside the device.

[0007] This causes problems such as not satisfying the receiving characteristics of SDI or U-SDI signals, changing video data, ancillary data, and timing reference codes, making it impossible to transmit signals between different devices, and also causing the device to fail the eye mask test of a specified standard.

[0008] A method for measuring the resistance of equipment equipped with a video input circuit to ISI (InterSymbol Interference) is described, for example, in Patent Application Publication No. 2020-63223, which was made by the same applicant as this patent application and was unpublished at the time of filing this patent application.

[0009] This method sends out a video signal while varying the amount of deterministic jitter by changing the amplitude of the electrical differential signal and the gain of the emphasis filter, and measures the tolerance based on the amount of jitter at which signal transmission between the video transmitting device and the video receiving device becomes impossible.

[0010] In addition to ISI, jitter in electrical differential signals also includes periodic jitter (jitter that is uncorrelated with the data pattern and occurs periodically) caused by ripples in the power regulator or simultaneous switching noise using multiple I / Os. The method for measuring tolerance described above generates periodic jitter by varying the switching frequency of the power regulator. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent No. 5744337 [Non-patent literature]

[0012] [Non-Patent Document 1] SMPTE ST2082-1:2015,“SMPTE STANDARD 12Gb / s Signal / Data Serial Interface - Electrical” [Non-Patent Document 2] ARIB STD-B58, "Super High Definition Television Signal Studio Equipment Interface Standard" Summary of the Invention [Problem to be solved by the invention]

[0013] The above method can adjust the frequency of period jitter by varying the switching frequency of the power regulator. However, depending on the power regulator, it may not be possible to adjust the amount of jitter sufficiently.

[0014] In addition, in the above-mentioned method, it is necessary to vary the amount of ripple in the power regulator in order to add periodic jitter to the video signal. However, in order to vary the amount of ripple, it is necessary to change the constant of the decoupling capacitor mounted around the power regulator or to vary the load capacitance, which is not a simple method.

[0015] The present invention has been made to solve the above problems, and its object is to provide a signal generating device that can easily vary the frequency and amount of periodic jitter when adding jitter to a predetermined signal such as a video signal. An error tolerance evaluation apparatus that includes a signal generation apparatus and is capable of evaluating error tolerance against jitter using the signal generation apparatus The purpose of this invention is to provide [Means for solving the problem]

[0016] In order to solve the above problem, the present invention provides the following: Error tolerance evaluation apparatus is the signal with added jitter In an error tolerance evaluation apparatus that evaluates error tolerance of an external device against the jitter, a signal generation apparatus that generates a signal with the jitter added thereto, the signal generated by the signal generation apparatus, and a signal including a bit error generated when the signal is input in the external device are compared, and an error measurement circuit that measures an error indicating a BER (bit error rate), the number of bit errors, a CRC (cyclic redundancy check) error rate, or the number of CRC errors is provided, and the signal generation apparatus a signal transmission circuit for transmitting a differential signal by two signal lines; an induced signal transmission circuit for generating a periodic differential induced signal by two signal lines reflecting a predetermined frequency f and transmitting the induced signal; and a transmission line having a plurality of coupling lines, any one of the plurality of coupling lines being designated, wherein each of the plurality of coupling lines comprises a dielectric, and two signal wirings and two induced wirings formed in parallel on a surface of the dielectric, and the wiring interval between the two signal wirings is set to s V, the wiring interval between the adjacent signal wiring and the guiding wiring is p, and the wiring interval between the two guiding wirings is s A The width of the signal wiring is w V The width of the guiding wire is w A , the wiring length of the two signal wirings and the two guidance wirings is L, the height of the dielectric is h, and the relative dielectric constant of the dielectric is ε r the signal transmitted by the signal transmitting circuit is transmitted through the two signal wirings, and the induced signal transmitted by the induced signal transmitting circuit is transmitted through the two induced wirings, whereby the jitter is added to the signal by crosstalk from the induced signal to the signal, and the jitter is increased by a factor of 10 to 15 at the frequency f and the wiring interval s. V ,p,s A , the wiring width w V ,w A , the wiring length L, the height h, and the relative dielectric constant ε r Determined by , the error measurement circuit outputs an output process for outputting an element number i (i is an integer satisfying 1 ≦ i ≦ N (N is the number of the plurality of coupling lines)) for designating any one of the plurality of coupling lines provided in the transmission line provided in the signal generation apparatus to the signal generation apparatus, so that the signal generation apparatus generates a signal with the jitter added thereto corresponding to the element number i, inputs the signal with the jitter added thereto corresponding to the element number i from the signal generation apparatus as a first signal, inputs a signal including a bit error generated when the first signal is input in the external device from the external device as a second signal, and performs a measurement process for measuring the error by comparing the first signal and the second signal. When the value of the error is smaller than a preset threshold value starting from the element number i = 1, with the amount of the jitter increasing monotonically as the element number i increases, a process of adding 1 to the element number i, the output process, the input process, and the measurement process are repeated to obtain the relationship between the error measured in the measurement process and the jitter , characterized in that

[0017] Also, claim 2 Error tolerance evaluation apparatus is a multi-link signal with jitter added, which is a signal consisting of multiple links. The error tolerance evaluation device evaluates the error tolerance of an external device against the jitter using the above-mentioned method, the error tolerance evaluation device comprising: a signal generating device that generates a multi-link signal to which the jitter has been added; and an error measuring circuit that measures an error indicating a BER (bit error rate), a number of bit errors, a CRC (cyclic redundancy check) error rate, or a number of CRC errors by comparing the signal generated by the signal generating device with a multi-link signal including a bit error generated in association with an input of the signal in the external device, wherein the signal generating device: The method includes a signal transmission circuit, an induced signal transmission circuit, and a transmission line for each of the plurality of links, the signal transmission circuit generates a differential signal by two signal lines, the induced signal transmission circuit is designated a predetermined frequency f, generates a periodic differential induced signal by two signal lines reflecting the frequency f, and transmits the induced signal, the transmission line has a plurality of coupled lines, any one of the plurality of coupled lines is designated, each of the plurality of coupled lines includes a dielectric, and two signal wires and two induced wires formed to run in parallel on a surface of the dielectric, and a wiring interval between the two signal wires is set to s. V , the wiring interval between the adjacent signal wiring and the guiding wiring is p, and the wiring interval between the two guiding wirings is s A The width of the signal wiring is w V The width of the guiding wire is w A, the wiring length of the two signal wirings and the two guidance wirings is L, the height of the dielectric is h, and the relative dielectric constant of the dielectric is ε r the signal transmitted by the signal transmitting circuit is transmitted through the two signal wirings, and the induced signal transmitted by the induced signal transmitting circuit is transmitted through the two induced wirings, whereby the jitter is added to the signal by crosstalk from the induced signal to the signal, and the jitter is increased by a factor of 10 to 15 at the frequency f and the wiring interval s. V ,p,s A , the wiring width w V ,w A , the wiring length L, the height h, and the relative dielectric constant ε r Determined by the error measuring circuit performs an output process of outputting to the signal generating device an element number i (i is an integer satisfying 1≦i≦N (N is the number of the plurality of coupled lines)) for specifying any one of the plurality of coupled lines in the transmission line provided in the signal generating device, thereby generating a multi-link signal having the jitter added thereto corresponding to the element number i, and inputting the multi-link signal having the jitter added thereto corresponding to the element number i as a first signal from the signal generating device, and When performing an input process of inputting a multi-link signal including a bit error generated with the input of a first signal as a second signal, and a measurement process of measuring the error by comparing the first signal with the second signal, the amount of jitter increases monotonically with an increase in element number i, and when the value of the error is smaller than a preset threshold value starting from element number i=1, a process of adding 1 to element number i, the output process, the input process, and the measurement process are repeated to obtain a relationship between the error measured in the measurement process and the jitter. , characterized in that

[0018] Also, claim 3 Error tolerance evaluation device The present invention relates to a method for producing a Error tolerance evaluation device In The signal generating device has a transmission line. Each of the multiple coupled lines includes the dielectric, the two signal wires formed in parallel on a surface of the dielectric, and the two guiding wires formed adjacent to the two signal wires.

[0019] Also, claim 4 Error tolerance evaluation device The present invention relates to a method for producing a Error tolerance evaluation device In The signal generating device has a transmission line. Each of the plurality of coupled lines includes the dielectric, the two signal wirings formed in parallel on a surface of the dielectric, and the two guiding wirings formed to sandwich the two signal wirings, and the wiring interval between the two signal wirings is set to s V The wiring interval between the wiring that transmits the induced signal on the positive side of the two guiding wirings and one of the two signal wirings is p1, the wiring interval between the wiring that transmits the induced signal on the negative side of the two guiding wirings and the other of the two signal wirings is p2, and the wiring width of the signal wiring is w V The width of the guiding wire is w A, the wiring length of the two signal wirings and the two guidance wirings is L, the height of the dielectric is h, and the relative dielectric constant of the dielectric is ε r the signal transmitted by the signal transmitting circuit is transmitted through the two signal wirings, and the induced signal transmitted by the induced signal transmitting circuit is transmitted through the two induced wirings, whereby the jitter is added to the signal by crosstalk from the induced signal to the signal, and the jitter is increased by a factor of 10 to 15 at the frequency f and the wiring interval s. V , p1, p2, the wiring width w V ,w A , the wiring length L, the height h, and the relative dielectric constant ε r The present invention is characterized in that the above-mentioned is determined by the above-mentioned formula.

[0020] Also, claim 5 Error tolerance evaluation device The present invention relates to a method for producing a Error tolerance evaluation device In The signal generating device has a transmission line. Each of the plurality of coupled lines includes the dielectric, the two signal wirings and the two guiding wirings formed in parallel on a surface of the dielectric, and a second dielectric layered on the dielectric and disposed to cover the two signal wirings and the two guiding wirings, and the wiring interval between the two signal wirings is set to s V , the wiring interval between the adjacent signal wiring and the guiding wiring is p, and the wiring interval between the two guiding wirings is s A The width of the signal wiring is w V The width of the guiding wire is w A The length of the two signal wires and the two guiding wires is L, the height of the dielectric is h1, and the relative dielectric constant of the dielectric is ε r1 , the height of the second dielectric is h2, and the relative dielectric constant of the second dielectric is ε r2 the signal transmitted by the signal transmitting circuit is transmitted through the two signal wirings, and the induced signal transmitted by the induced signal transmitting circuit is transmitted through the two induced wirings, whereby the jitter is added to the signal by crosstalk from the induced signal to the signal, and the jitter is increased by a factor of 10 to 15 at the frequency f and the wiring interval s. V ,p,s A, the wiring width w V ,w A , the wiring length L, the heights h1 and h2, and the relative dielectric constant ε r1 ,ε r2 The present invention is characterized in that the above-mentioned is determined by the above-mentioned formula. Effect of the Invention

[0022] As described above, according to the present invention, when adding jitter to a predetermined signal such as a video signal, the frequency and amount of period jitter can be easily varied, It is possible to evaluate the error tolerance against jitter. . [Brief description of the drawings]

[0023] [Figure 1] 1 is a block diagram showing an example of the configuration of a signal generating device provided in an error tolerance evaluation device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a configuration example of a transmission line. [Diagram 3] FIG. 2 is a diagram illustrating a first configuration example of a coupled line. [Figure 4] 1 is a block diagram showing an example of the configuration of a signal generating device when jitter is added to a multilink signal; [Diagram 5] 1 is a block diagram showing an example of the configuration of a transmission line when jitter is added to a multilink signal; [Figure 6] FIG. 13 is a diagram for explaining a measurement result (A) when jitter is added to a multilink signal. [Figure 7] FIG. 13 is a diagram for explaining the measurement results (B) when jitter is added to a multilink signal. [Figure 8] FIG. 11 is a diagram illustrating a second configuration example of a coupled line. [Figure 9] 11A and 11B are diagrams illustrating a third configuration example of a coupled line. [Figure 10] 13 is a diagram illustrating a fourth configuration example of a coupled line. FIG. [Figure 11] FIG. 11 is a cross-sectional view for explaining a fifth configuration example of a coupled line. [Figure 12]FIG. 1 is a schematic diagram showing an example of the configuration of an entire system for evaluating error tolerance to periodic jitter. [Figure 13] 13 is a flowchart showing an example of processing by an error measurement circuit; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. The present invention controls the jitter when an induced signal is added to a predetermined signal by adjusting the capacitive coupling and the inductive coupling of a transmission line through which the predetermined signal to which the jitter is added and the induced signal are transmitted. and evaluates the error tolerance of external equipment to jitter based on the signal to which jitter has been added. The present invention is characterized by the above.

[0025] [Signal Generator] First, according to an embodiment of the present invention Equipped with an error tolerance evaluation device A signal generating device according to an embodiment of the present invention will be described. Equipped with an error tolerance evaluation device 1 is a block diagram showing an example of the configuration of a signal generating device 1. The signal generating device 1 includes a video signal transmitting circuit 10, an induced signal transmitting circuit 11, a jitter characteristic control circuit 12, a transmission line (jitter adding circuit) 13, a video signal output circuit 14, and an induced signal output circuit 15.

[0026] The video signal transmission circuit 10 generates the video signal to which jitter is to be added as a differential (opposite phase) signal (differential signal (positive differential signal P and negative differential signal N)) using two signal lines, or inputs it from outside, and transmits the video signal which is a differential signal. The video signal is, for example, a signal in which the video signal data is coded using a transmission line code such as an NRZ signal or a PAM signal.

[0027] The induced signal transmission circuit 11 receives a frequency (toggle rate) f(i) from the jitter characteristics control circuit 12, generates a periodic induced signal reflecting the frequency f(i) as a differential signal (differential signal) by two signal lines, and transmits the induced signal, which is a differential signal. The induced signal is, for example, a periodic signal, a pseudo-random pattern such as PRBS (Pseudo-Random Binary Sequence), or a signal in which data such as a video signal is coded using a transmission line code.

[0028] The jitter characteristics control circuit 12 is a circuit that controls the characteristics of the jitter added to the video signal by the transmission line 13. The jitter characteristics control circuit 12 manually or automatically specifies an element number i in accordance with a user's operation so as to generate a jitter (deterministic jitter) J(i) desired by the user. Then, the jitter characteristics control circuit 12 specifies a frequency f(i) of an induced signal corresponding to the element number i, and any one of the coupled lines 21-1 to 21-N described later. Here, the element number i is an integer that satisfies 1≦i≦N, where N is the number of elements. The frequency f(i) of the induced signal is also the frequency of the periodic jitter.

[0029] The jitter characteristic control circuit 12 outputs the frequency f(i) to the induction signal transmitting circuit 11 and also outputs the element number i to the transmission line 13 .

[0030] As a result, a periodic induced signal reflecting the frequency f(i) is generated in the induced signal transmitting circuit 11. Furthermore, in the transmission line 13, crosstalk occurs from the induced signal to the video signal due to capacitive coupling and inductive coupling when the video signal and the induced signal are transmitted using the coupling line 21-i corresponding to element number i. Then, this crosstalk causes the induced signal to interfere with the video signal, and jitter having desired characteristics is added to the video signal.

[0031] The transmission line 13 receives an element number i from the jitter characteristic control circuit 12 and switches to a coupling line 21-i corresponding to the element number i among coupling lines 21-1 to 21-N described later. The transmission line 13 also transmits a video signal transmitted from the video signal transmission circuit 10 and a induced signal transmitted from the induced signal transmission circuit 11.

[0032] The transmission line 13 adds jitter J(i) to the video signal due to crosstalk from the induced signal to the video signal caused by capacitive coupling and inductive coupling by transmitting the video signal and the induced signal via the coupled line 21-i. This jitter J(i) is determined by various parameters such as the frequency f(i) of the induced signal and the configuration of the coupled line 21-i.

[0033] The transmission line 13 outputs the video signal with the jitter added to a video signal output circuit 14, and outputs the induced signal to an induced signal output circuit 15. The transmission line 13, the jitter J(i), and the parameters will be described in detail later.

[0034] The video signal output circuit 14 receives the video signal with jitter added from the transmission line 13, and performs a predetermined output interface process (e.g., electrical / optical conversion process) on the video signal. Then, the video signal output circuit 14 outputs the video signal that has been subjected to the predetermined output interface process. For example, the video signal output circuit 14 generates and outputs a bit pattern in accordance with the ARIB STD-B58 standard.

[0035] The induced signal output circuit 15 receives the induced signal from the transmission line 13 and processes the induced signal through a predetermined output interface. The induced signal output circuit 15 then outputs the induced signal that has been processed through the predetermined output interface. The induced signal output circuit 15 may be a termination resistor. In this case, the induced signal output circuit 15 does not output the induced signal.

[0036] (Transmission Line 13) Next, a detailed description will be given of the transmission line 13 shown in Fig. 1. Fig. 2 is a block diagram showing an example of the configuration of the transmission line 13. This transmission line 13 includes switching circuits 20 and 22 and coupled lines (microstrip lines) 21-1 to 21-N.

[0037] The switching circuit 20 receives an element number i (1≦i≦N) from the jitter characteristic control circuit 12 and switches the cross points of the coupled lines 21-1 to 21-N from the already selected lines to the coupled line 21-i corresponding to the element number i.

[0038] The switching circuit 20 transmits the video signal transmitted from the video signal transmitting circuit 10 and the induction signal transmitted from the induction signal transmitting circuit 11 to the switching circuit 22 via the coupling line 21-i.

[0039] The coupled lines 21-1 to 21-N are made up of N coupled lines having different amounts of capacitive coupling and inductive coupling.

[0040] The coupled line 21-i (i.e., each of the coupled lines 21-1 to 21-N) transmits the video signal and the induced signal via the switching circuit 20, thereby adding jitter to the video signal due to crosstalk from the induced signal to the video signal caused by capacitive coupling and inductive coupling.

[0041] As described above, the jitter J(i) generated in the coupled line 21-i is determined by various parameters such as the frequency f(i) of the induced signal and the configuration of the coupled line 21-i, etc. Therefore, when one or more parameters such as the frequency f(i) of the induced signal and the configuration of the coupled line 21-i are different between the coupled lines 21-1 to 21-N, different jitters are added to the video signal.

[0042] The user recognizes in advance the jitter characteristics corresponding to parameters such as the frequency f(i) of the induced signal and the configuration of the coupled line 21-i for each element number i. The jitter characteristics control circuit 12 shown in Fig. 1 manually specifies the frequency f(i) of the induced signal corresponding to the jitter characteristics and the coupled line 21-i, or automatically, as in the case of an error tolerance evaluation device 3 shown in Fig. 12, which will be described later. In other words, the jitter characteristics control circuit 12 specifies the element number i so that a predetermined jitter is generated.

[0043] The coupled line 21-i outputs the video signal to which the jitter has been added and the input and transmitted induced signal to the switching circuit 22. The coupled line 21-i will be described in detail later.

[0044] The switching circuit 22 receives an element number i (1≦i≦N) from the jitter characteristic control circuit 12, and switches the cross points of the coupled lines 21-1 to 21-N from the already selected line to the coupled line 21-i corresponding to the element number i.

[0045] The switching circuit 22 inputs the jitter-added video signal and the induced signal from the coupled line 21-i, outputs the jitter-added video signal to the video signal output circuit 14, and outputs the induced signal to the induced signal output circuit 15.

[0046] When N=1, the transmission line 13 does not need to include the switching circuits 20 and 22 since it includes one coupled line 21-1.

[0047] (Coupling line 21-i / first configuration example) Next, the coupled lines 21-1 to 21-N (coupled lines 21-i) will be described in detail. Fig. 3 is a diagram illustrating a first configuration example of the coupled line 21-i.

[0048] This coupled line 21-i is configured to include a dielectric 30, a GND (ground) layer 31 laminated on the dielectric 30, and video wiring 32-1, 32-2 and guidance wiring 33-1, 33-2 that are arranged on the opposite side of the dielectric 30 from the GND layer 31 and are formed to run parallel to the surface (outer layer) of the dielectric 30.

[0049] The video wirings 32-1, 32-2 and the guidance wirings 33-1, 33-2 are disposed parallel to each other on the surface of the dielectric 30. The video signals transmitted through the video wirings 32-1, 32-2 and the guidance signals transmitted through the guidance wirings 33-1, 33-2 share the GND layer 31.

[0050] As described above, the video signal and the guiding signal are both differential signals. The video wiring 32-1 is a line through which the positive differential signal P of the two video signals is transmitted, and the video wiring 32-2 is a line through which the negative differential signal N of the two video signals is transmitted. The guiding wiring 33-1 is a line through which the positive differential signal P of the two guiding signals is transmitted, and the guiding wiring 33-2 is a line through which the negative differential signal N of the two guiding signals is transmitted.

[0051] The wiring distance between the two video wirings 32-1 and 32-2 that transmit the video signal is s V (i), the wiring interval between the video wirings 32-1, 32-2 and the guidance wirings 33-1, 33-2 (the wiring interval between the adjacent video wirings 32-1 and guidance wirings 33-2 in FIG. 3) is p(i). In addition, the wiring interval between the two guidance wirings 33-1, 33-2 that transmit guidance signals is s A (i).

[0052] The wiring width (cross-sectional size) of the video wiring 32-1 and 32-2 is w V (i) The wiring width of the guiding wiring 33-1, 33-2 is w A (i), the length of the video wiring 32-1, 32-2 and the guidance wiring 33-1, 33-2 running in parallel on the surface in the longitudinal direction of the dielectric 30 is L(i). The height of the dielectric 30 is h(i), and the relative dielectric constant of the dielectric 30 is ε r(i) The frequency of the induced signal (the frequency of the periodic jitter) is f(i).

[0053] In the coupled line 21-i, the jitter J(i) that the induced signal flowing through the induced wirings 33-1 and 33-2 gives to the video wirings 32-1 and 32-2 is determined by the above-mentioned wiring interval s V Using parameters such as (i), it is expressed by the following function g(·). [Number 1] J(i) = g(s V (i), p(i), s A (i), w V (i), w A (i), L(i), h(i), ε r (i),f(i)) (1)

[0054] The above formula (1) is derived from the fact that the video wirings 32-1, 32-2 and the guidance wirings 33-1, 33-2 are capacitively coupled (electrostatically coupled) and inductively coupled (electromagnetically coupled).

[0055] In the formula (1), for example, the narrower the wiring interval p(i) between the video wiring 32-1 and the guiding wiring 33-2, the larger the jitter J(i) (the amount of jitter), and the wider the wiring interval p(i), the smaller the jitter J(i). This is because the closer the video wiring 32-1, 32-2 and the guiding wiring 33-1, 33-2 are physically, the stronger the degree of coupling and the greater the crosstalk, and the farther apart they are, the weaker the degree of coupling and the less the crosstalk.

[0056] In addition, for example, the wiring interval s between the video wirings 32-1 and 32-2 V (i) is wide, and the wiring interval s of the guiding wiring 33-1, 33-2 A The narrower the distance s(i), the larger the jitter J(i). V (i) is narrow, and the wiring interval s of the guiding wiring 33-1, 33-2 A The wider (i), the smaller the jitter J(i).

[0057] Also, for example, the longer the wiring length L(i) of the video wiring 32-1, 32-2 and the guidance wiring 33-1, 33-2, the larger the jitter J(i) becomes, and the shorter the wiring length L(i), the smaller the jitter J(i).

[0058] In addition, the wiring width w of the video wiring 32-1, 32-2 V (i) Wiring width w of the guiding wiring 33-1, 33-2 A (i), the height h(i) of the dielectric 30, and the relative dielectric constant ε of the dielectric 30 r Regarding (i) and the frequency f(i) of the induced signal, they indirectly affect the jitter J(i) in relation to other parameters.

[0059] 1 includes N types of coupled lines 21-1 to 21-N each having one or more different parameters among all parameters other than frequency f(i). In this case, the frequency f(i) of the induced signal may be a different value for each element number i, or may be the same value.

[0060] In addition, when the frequency f(i) of the induced signal is a different value for each element number i, the transmission line 13 of the signal generating device 1 may be provided with coupled lines 21-1 to 21-N (coupled lines 21-1 to 21-N having the same configuration, etc.) in which parameters other than the frequency f(i) are the same between element numbers i.

[0061] As described above, the jitter characteristics control circuit 12 designates an element number i in order to generate a jitter J(i) desired by the user in the coupled line 21-i.

[0062] As a result, the element number i is specified in the jitter characteristics control circuit 12, whereby the frequency f(i) of the induced signal, i.e., the frequency f(i) of the jitter J(i), and the coupling line 21-i are identified, and the jitter J(i) added to the video signal can be controlled.

[0063] In the coupled line 21-i shown in Fig. 3, crosstalk from the induced signal to the video signal adds jitter to the video signal, but this crosstalk is converted into jitter regardless of the positive and negative of the crosstalk component. In this case, the direction of the current flowing through the video wiring 32-1, 32-2 and the induced wiring 33-1, 33-2 does not matter. In general, reversing the direction of either one of them reverses the positive and negative of the crosstalk component, and reversing the direction of both restores the positive and negative of the crosstalk component. The same applies to Fig. 8, etc., which will be described later.

[0064] (The parameters other than the basic shape and wiring interval p(i) of the coupled line 21-i are the same.) Here, the basic form of the coupled line 21-i will be described. The basic form of the coupled line 21-i is the case where the parameters other than the wiring interval p(i) between the video wiring 32-1 and the guidance wiring 33-2 are the same. In this case, the jitter J(i) generated in the coupled line 21-i is expressed by the following formula. [Number 2] J(i) = g(p(i)) (2)

[0065] The formula (2) is a simplification of the formula (1) and indicates that the jitter J(i) changes when the wiring interval p(i) is changed. In the formula (2), the narrower the wiring interval p(i), the larger the jitter J(i) becomes, and the wider the wiring interval p(i), the smaller the jitter J(i).

[0066] In this basic form, the transmission line 13 of the signal generating device 1 includes N types of coupled lines 21-1 to 21-N with different wiring intervals p(i). The jitter characteristics control circuit 12 specifies an element number i so that the coupled line 21-i generates the jitter J(i) desired by the user. In this case, the frequency f(i) has a common value among the coupled lines 21-1 to 21-N.

[0067] As a result, by specifying the element number i in the jitter characteristics control circuit 12, the frequency f(i) of the induced signal and the coupled line 21-i are identified, and the jitter J(i) added to the video signal can be controlled according to the different wiring intervals p(i) between the coupled lines 21-1 to 21-N.

[0068] (The other first configurations of the coupled lines 21-i are the same except for the parameters of the frequency f(i)) Next, another first form of the coupled line 21-i will be described. The other first form of the coupled line 21-i is a case where the parameters other than the frequency f(i) of the induced signal are the same. In this case, the jitter J(i) generated in the coupled line 21-i is expressed by the following formula. [Number 3] J(i) = g(f(i)) (3)

[0069] The formula (3) is a simplification of the formula (1) and indicates that the frequency of the jitter J(i) is changed by changing the frequency f(i). This is because the frequency of the jitter J(i) depends on the frequency f(i) of the induced signal. In the formula (3), the higher the frequency f(i), the higher the frequency of the jitter J(i), and the lower the frequency f(i), the lower the frequency of the jitter J(i).

[0070] When a pseudo-random pattern such as PRBS is used as the inducement signal, the frequency characteristics of the jitter J(i) become random according to the period of the inducement signal. Therefore, by periodically changing the inducement signal, the frequency of the jitter J(i) added to the video signal can be changed.

[0071] In this embodiment, the transmission line 13 of the signal generating device 1 has a wiring interval s V (i), p(i), s A (i), wiring width w V (i), w A (i), wiring length L(i), height h(i) and relative dielectric constant ε r (i) has identical coupled lines 21-1 to 21-N.

[0072] The jitter characteristic control circuit 12 designates an element number i in order to generate a jitter J(i) desired by the user in the coupled line 21-i.

[0073] As a result, by specifying the element number i in the jitter characteristics control circuit 12, the frequency f(i) of the induced signal is specified, and the jitter J(i) added to the video signal can be controlled according to the different frequencies f(i) between element numbers 1 to N.

[0074] (The other second forms of the coupled lines 21-i are the same except for the wiring length L(i)) Next, another second form of the coupled line 21-i will be described. The other second form of the coupled line 21-i is a case where the parameters other than the wiring length L(i) of the video wiring 32-1, 32-2 and the guidance wiring 33-1, 33-2 are the same. In this case, the jitter J(i) generated in the coupled line 21-i is expressed by the following formula. [Number 4] J(i) = g(L(i)) (4)

[0075] The above formula (4) is a simplification of the above formula (1), and indicates that the jitter J(i) changes when the line length L(i) is changed.

[0076] As described above, the video signal and the induced signal are each a differential signal. Therefore, two types of propagation modes, odd mode and even mode, exist in the lines of the differential signals P and N in the video wiring 32-1, 32-2 and the guiding wiring 33-1, 33-2, and the propagation speed differs between the two types of propagation modes. Since the difference in delay time between the propagation modes increases in proportion to the wiring length L(i), the crosstalk also increases in proportion to the wiring length L(i).

[0077] Therefore, in the above formula (4), the longer the wiring length L(i), the larger the jitter J(i) becomes, and the shorter the wiring length L(i), the smaller the jitter J(i).

[0078] In this embodiment, the transmission line 13 of the signal generating device 1 includes N types of coupled lines 21-1 to 21-N having different wiring lengths L(i). The jitter characteristics control circuit 12 specifies an element number i to generate a jitter J(i) desired by the user. In this case, the frequency f(i) has a common value among the coupled lines 21-1 to 21-N.

[0079] As a result, the jitter characteristics control circuit 12 specifies the element number i, thereby identifying the coupled line 21-i, and the jitter J(i) added to the video signal can be controlled according to the different wiring lengths L(i) between the coupled lines 21-1 to 21-N.

[0080] As described above, according to the signal generating device 1 shown in FIG. 1, the video signal transmitting circuit 10 transmits a video signal, and the guidance signal transmitting circuit 11 generates and transmits a periodic guidance signal that reflects the frequency f(i).

[0081] The jitter characteristic control circuit 12 specifies an element number i and identifies the frequency f(i) of the induced signal and the coupled line 21-i corresponding to the element number i so as to generate the jitter J(i) desired by the user.

[0082] The transmission line 13 transmits the video signal and the induced signal via the coupling line 21-i, and the video signal is subjected to crosstalk from the induced signal to the video signal due to capacitive coupling and inductive coupling, with a wiring interval s V Jitter J(i) is added according to parameters such as (i).

[0083] This allows the jitter J(i) desired by the user to be generated according to the frequency f(i) of the induced signal corresponding to the specified element number i and the configuration of the coupled line 21-i, and the jitter J(i) is added to the video signal.

[0084] In other words, the frequency f(i) of the period jitter can be easily varied by changing the parameter of the frequency f(i) of the induced signal. Also, the amount of period jitter can be easily varied by changing the parameter other than the frequency f(i) of the induced signal (the wiring interval s V(i), that is, by switching the coupled lines 21-i. Therefore, when adding jitter to a video signal, the frequency and amount of period jitter can be easily changed.

[0085] [Signal Generator / Multilink Signal] Next, a signal generating device for adding jitter to a multi-link signal consisting of video signals of a plurality of links will be described. Fig. 4 is a block diagram showing an example of the configuration of a signal generating device for adding jitter to a multi-link signal.

[0086] Since a multilink signal needs to be transmitted without bit errors on all links, components for a maximum of M links are required on the board of the signal generating device 2, excluding the jitter characteristic control circuit 12. M indicates the number of links and is an integer.

[0087] The multilink signal is a signal composed of multiple links, such as a U-SDI signal conforming to the above-mentioned Non-Patent Document 2, and is a signal composed of video signals corresponding to each of the multiple links. In the above-mentioned Non-Patent Document 2, the multilink signal is composed of one U-SDI signal by 24 links of 10G link signals.

[0088] This signal generating device 2 includes video signal transmitting circuits 10-1 to 10-M with M links, induced signal transmitting circuits 11-1 to 11-M with M links, a jitter characteristic control circuit 12, transmission lines (jitter adding circuits) 13-1 to 13-M with M links, video signal output circuits 14-1 to 14-M with M links, and induced signal output circuits 15-1 to 15-M with M links.

[0089] The components corresponding to the first link are the video signal transmission circuit 10-1, the guidance signal transmission circuit 11-1, the transmission line 13-1, the video signal output circuit 14-1, and the guidance signal output circuit 15-1. The components corresponding to the Mth link are the video signal transmission circuit 10-M, the guidance signal transmission circuit 11-M, the transmission line 13-M, the video signal output circuit 14-M, and the guidance signal output circuit 15-M.

[0090] The signal generator 2 adds jitter J(i,1) (to be described later) to the video signal corresponding to the first link, and adds jitter J(i,M) to the video signal corresponding to the Mth link.

[0091] Here, m is a link number and is an integer satisfying 1≦m≦M. For the m-th link, the signal generating device 2 includes a video signal transmitting circuit 10-m, a guided signal transmitting circuit 11-m, a transmission line 13-m, a video signal output circuit 14-m, and a guided signal output circuit 15-m, and adds jitter J(i,m) to the video signal corresponding to the m-th link. The signal generating device 2 includes a common jitter characteristics control circuit 12 for the M number of links.

[0092] The video signal transmission circuit 10-m for each link corresponds to the video signal transmission circuit 10 shown in Figure 1, the induced signal transmission circuit 11-m corresponds to the induced signal transmission circuit 11, the transmission line 13-m corresponds to the transmission line 13, the video signal output circuit 14-m corresponds to the video signal output circuit 14, the induced signal output circuit 15-m corresponds to the induced signal output circuit 15, and the jitter characteristic control circuit 12 corresponds to the jitter characteristic control circuit 12.

[0093] The video signal transmission circuit 10-m generates a video signal as a differential signal using two signal lines, or receives an externally input video signal and transmits the video signal as a differential signal.

[0094] The induced signal transmitting circuit 11-m inputs the frequency f(i, m) from the jitter characteristic control circuit 12, generates a periodic induced signal reflecting the frequency f(i, m) as a differential signal via two signal lines, and transmits the induced signal.

[0095] The jitter characteristics control circuit 12 specifies an element number i so that a jitter J(i,m) desired by a user is generated. Then, the jitter characteristics control circuit 12 specifies, for each link, a frequency f(i,m) of an induced signal corresponding to the element number i, and any one of the coupled lines 21-im among the coupled lines 21-1-m to 21-Nm. The frequency f(i,m) of the induced signal is also the frequency of the jitter J(i,m) added in the coupled line 21-im, which will be described later.

[0096] The jitter characteristic control circuit 12 outputs the frequency f(i,m) to the induction signal transmitting circuit 11-m, and also outputs the element number i to the transmission line 13-m.

[0097] The transmission line 13-m receives an element number i from the jitter characteristic control circuit 12 and switches to a coupling line 21-im corresponding to the element number i among coupling lines 21-1-m to 21-Nm described below. The transmission line 13-m transmits a video signal transmitted from the corresponding video signal transmission circuit 10-m, and transmits an induced signal transmitted from the corresponding induced signal transmission circuit 11-m.

[0098] The transmission line 13-m adds jitter J(i,m) to the video signal due to crosstalk caused by capacitive coupling and inductive coupling, and outputs the video signal with the added jitter J(i,m) to the corresponding video signal output circuit 14-m. The transmission line 13-m also outputs the induced signal to the corresponding induced signal output circuit 15-m. Details of the transmission lines 13-1 to 13-M and the jitter J(i,m) will be described later.

[0099] The video signal output circuit 14-m receives the video signal with jitter J(i,m) added from the corresponding transmission line 13-m, and performs a predetermined output interface process on the video signal. Then, the video signal output circuit 14-m outputs the video signal that has been subjected to the predetermined output interface process.

[0100] The induced signal output circuit 15-m receives the induced signal from the corresponding transmission line 13-m, processes the induced signal by a predetermined output interface, and outputs the induced signal that has been processed by the predetermined output interface.

[0101] (Transmission lines 13-1 to 13-M) Next, a detailed description will be given of the transmission lines 13-1 to 13-M shown in Fig. 4. Fig. 5 is a block diagram showing an example of the configuration of the transmission lines 13-1 to 13-M.

[0102] The transmission lines 13-1 to 13-M include switching circuits 20-1 to 20-M with M links, coupled lines 21-i-1 to 21-iM with M links, and switching circuits 22-1 to 22-M with M links.

[0103] That is, the transmission line 13-m for each link includes a switching circuit 20-m, coupled lines 21-1-m to 21-Nm, and a switching circuit 22-m.

[0104] The transmission line 13-m for each link is similar to the transmission line 13 shown in Fig. 2. The switching circuit 20-m corresponds to the switching circuit 20, the coupled lines 21-1-m to 21-Nm correspond to the coupled lines 21-1 to 21-N, and the switching circuit 22-m corresponds to the switching circuit 22, so a description of each component will be omitted.

[0105] When N=1, the transmission lines 13-1 to 13-M do not need to include the switching circuits 20-1 to 20-M and the switching circuits 22-1 to 22-M.

[0106] The configuration of the coupled lines 21-1-m to 21-Nm (coupled line 21-im) for each link is similar to the configuration of the coupled line 21-i shown in Fig. 3. In the coupled lines 21-im for each link, a predetermined distance is ensured between the links so as to prevent interference between the links.

[0107] The wiring distance between the two video wirings 32-1 and 32-2 that transmit the video signal is s VThe wiring distance between the video wiring 32-1 and the guidance wiring 33-2 is defined as p(i,m), and the wiring distance between the two guidance wirings 33-1 and 33-2 that transmit the guidance signal is defined as s A Let (i,m).

[0108] The wiring width of the video wiring 32-1 and 32-2 is w V (i,m), the wiring width of the guiding wiring 33-1, 33-2 is w A (i,m), the length of the video wiring 32-1, 32-2 and the guidance wiring 33-1, 33-2 running in parallel on the surface of the dielectric 30 in the longitudinal direction is L(i,m). The height of the dielectric 30 is h(i,m), and the relative dielectric constant of the dielectric 30 is ε r (i,m) and the frequency of the induced signal is f(i,m).

[0109] In the coupled line 21-im, the jitter J(i,m) that the induced signal flowing through the induced wirings 33-1, 33-2 gives to the video wirings 32-1, 32-2 is determined by the above-mentioned wiring interval s V It is expressed by the following function g(·) using parameters such as (i, m). [Number 5] J(i,m)=g(s V (i,m),p(i,m),s A (i,m),w V (i,m),w A (i,m),L(i,m),h(i,m),ε r (i,m),f(i,m)) (5)

[0110] In this way, by specifying the element number i in the jitter characteristics control circuit 12, it is possible to control the jitter J(i,m) added to each of the video signals of the M links that constitute the multilink signal.

[0111] (Measurement results) Next, we will explain the measurement results when jitter is added to a multilink signal. Figures 6 and 7 show the measurement results (A) and (B) when using the signal generator 2 shown in Figure 4, and show the results of measuring the jitter characteristics of a specific external device related to a specific link (link to be measured) using a sampling oscilloscope.

[0112] FIG. 6 is a diagram explaining the measurement result (A) when jitter is added to a multilink signal, and shows an example in which the number of links M=24, the video signal and induced signal of the link being measured are 15-stage PRBS signals (PRBS-15 signals), the video signals of the other links are U-SDI signals, and the induced signals of the other links are clock signals with a toggle rate of 10.681 Gbps.

[0113] FIG. 7 is a diagram explaining the measurement result (B) when jitter is added to a multilink signal, and is an example in which the number of links M=24, the video signal and induced signal of the link being measured are PRBS-15 signals, the video signals of other links are U-SDI signals, and the induced signals of other links are PRBS-15 signals.

[0114] (1) to (4) in FIG. 6 and (1) to (4) in FIG. 7 show histograms of jitter, with the horizontal axis indicating the deviation time (seconds) from the time of 1 UI and the vertical axis indicating the frequency.

[0115] 6 and 7(1) show histograms (composite histograms) of jitter depending on the data pattern (1.1), random jitter and periodic jitter (1.2), and total jitter (1.3).

[0116] In Figures 6 and 7 (2), in an enlarged histogram (Composite DDJ Histogram) of the jitter (1.1) that depends on the data pattern, (2.1) shows the histogram observed when transitioning from bit '1' to bit '0', (2.2) shows the histogram observed when transitioning from bit '0' to bit '1', and (2.3) shows the overall histogram. The histograms in (2.1) and (2.2) are almost the same.

[0117] Figures 6 and 7 (3) show histograms (RJ, PJ histograms) that enlarge only the random jitter and periodic jitter (1.2). The sampling oscilloscope used in this measurement cannot separate random jitter from periodic jitter, so only one histogram is shown. In the histogram in Figure 6 (3), the video signal wiring is subjected to electrical noise due to a periodic induced signal, resulting in two peaks, while the histogram in Figure 7 (3) shows one peak.

[0118] In Fig. 6 and Fig. 7 (4), a histogram (DDJ histogram) is shown in which only the jitter (1.1) that depends on the data pattern is enlarged. This histogram is the same as the histogram (2.3).

[0119] Figure 6 (5) shows the measured values ​​of period jitter PJ(δ-δ)=8.2ps, PJ(rms)=3.99ps, and Figure 7 (5) shows the measured values ​​of period jitter PJ(δ-δ)=2.4ps, PJ(rms)=1.58ps. The measured values ​​PJ(δ-δ) are an approximation of PJ based on the Dual-Dirac model, and the measured values ​​PJ(rms) are the RMS (Root Mean Square) value. For details on the Dual-Dirac model, see below. [Non-patent literature] Stephens, Ransom, “Jitter Analysis : The Dual-Dirac Model, RJ / DJ, and Q-Scale”, Agilent Technologies, Santa Clara, CA, Document 5989-3206EN, (2004)

[0120] Comparing FIG. 6 and FIG. 7, it can be seen that the shapes of the histograms of the period jitter and their measured values ​​are different, as shown in (3) and (5).

[0121] The signal generating device 2 shown in FIG. 4 can also be applied to cases where a video signal is mapped to multiple SDI signals and transmitted, and to a video interface consisting of multiple links such as DisplayPort, as described in the following non-patent documents 3 and 4. [Non-Patent Document 3] SMPTE ST2082-12:2016, “4320-line and 2160-line Source Image and Ancillary Data Mapping for Quad-link 12G-SDI” [Non-Patent Document 4] SMPTE ST425-5:2015, “Image Format and Ancillary Data Mapping for Quad-link 3 Gb / s Serial Interface”

[0122] As described above, according to the signal generating device 2 shown in FIG. 4, the video signal transmitting circuits 10-1 to 10-M transmit multilink signals, and the guiding signal transmitting circuits 11-1 to 11-M generate and transmit periodic guiding signals reflecting the frequencies f(i,1) to f(i,M).

[0123] The jitter characteristics control circuit 12 specifies an element number i and identifies frequencies f(i,1) to f(i,M) of induced signals and coupled lines 21-i-1 to 21-iM corresponding to the element number i so that the jitter J(i,1) to J(i,M) desired by the user is generated.

[0124] The transmission lines 13-1 to 13-M transmit the multilink signal and the induced signal via the coupling lines 21-i-1 to 21-iM, and thereby, the multilink signal is subjected to crosstalk from the induced signal to the multilink signal due to capacitive coupling and inductive coupling, with a wiring interval s V (i,1)~s V Jitter J(i,1) to J(i,M) is added according to parameters such as (i,M).

[0125] This makes it possible to generate jitter J(i,1) to J(i,M) desired by the user according to the frequencies f(i,1) to f(i,M) of the induced signals corresponding to the specified element number i and the configuration of the coupled lines 21-i-1 to 21-iM, and the jitter J(i,1) to J(i,M) is added to the multilink signal.

[0126] In other words, the frequencies f(i,1) to f(i,M) of the period jitter can be easily varied by changing the parameters of the frequencies f(i,1) to f(i,M) of the induced signals. Also, the amount of period jitter can be easily varied by changing the parameters other than the frequencies f(i,1) to f(i,M) of the induced signals (the wiring interval s V (i,1)~s V (i,M), that is, by switching the coupled lines 21-i-1 to 21-iM of element number i, the frequency and amount of period jitter can be easily varied. Therefore, when adding jitter to a multilink signal, the frequency and amount of period jitter can be easily varied.

[0127] (Coupling line 21-i / second configuration example) Next, a second configuration example of the coupled lines 21-1 to 21-N (coupled lines 21-i) shown in Fig. 3 will be described in detail. Fig. 8 is a diagram for explaining the second configuration example of the coupled line 21-i, showing a case where a video signal is sandwiched between induced signals. This configuration example also applies to the coupled lines 21-1-1 to 21-1-M, . . . , 21-N-1 to 21-NM (coupled lines 21-im) shown in Fig. 5. The same applies to Figs. 9 to 11 described later.

[0128] Similar to the first configuration example shown in FIG. 3, this coupling line 21-i is configured to include a dielectric 30, a GND layer 31 laminated on the dielectric 30, and video wiring 32-1, 32-2 and guidance wiring 33-1, 33-2 that are arranged on the opposite side of the dielectric 30 from the GND layer 31 and are formed parallel to the surface of the dielectric 30.

[0129] Comparing the first configuration example of the coupled line 21-i shown in FIG. 3 with the second configuration example of the coupled line 21-i shown in FIG. 8, both coupled lines 21-i have in common the fact that they have two video wirings 32-1, 32-2 and two guidance wirings 33-1, 33-2 that are formed in parallel on the surface of the dielectric 30.

[0130] In contrast, the second configuration example of the coupled line 21-i differs from the first configuration example of the coupled line 21-i in that the two guidance wires 33-1, 33-2 are formed to sandwich the two video wires 32-1, 32-2.

[0131] The wiring distance between the two video wirings 32-1 and 32-2 that transmit the video signal is s V (i), the wiring interval between the video wiring 32-1 transmitting the video signal of the positive side differential signal P and the guidance wiring 33-1 transmitting the induced signal of the positive side differential signal P is defined as p1(i). The wiring interval between the video wiring 32-2 transmitting the video signal of the negative side differential signal N and the guidance wiring 33-2 transmitting the induced signal of the negative side differential signal N is defined as p2(i). Other wiring widths w V The parameters such as (i) are assumed to be the same as those in the first configuration example shown in FIG.

[0132] In the coupled line 21-i, the jitter J(i) that the induced signal flowing through the induced wirings 33-1 and 33-2 gives to the video wirings 32-1 and 32-2 is determined by the above-mentioned wiring interval s V Using parameters such as (i), it is expressed by the following function g(·). [Number 6] J(i) = g(s V (i), p1(i), p2(i), w V (i),wA (i), L(i), h(i), ε r (i),f(i)) (6)

[0133] (Coupling line 21-i / third configuration example) Next, a detailed description will be given of a third configuration example of the coupled lines 21-1 to 21-N (coupled lines 21-i) shown in Fig. 3. Fig. 9 is a diagram for explaining the third configuration example of the coupled line 21-i, in which the polarity of the induced signal is inverted compared to the second configuration example of the coupled line 21-i shown in Fig. 8.

[0134] Similar to the second configuration example shown in FIG. 8, this coupling line 21-i is configured to include a dielectric 30, a GND layer 31 laminated on the dielectric 30, and video wiring 32-1, 32-2 and guidance wiring 33-1, 33-2 that are arranged on the opposite side of the dielectric 30 from the GND layer 31 and are formed parallel to the surface of the dielectric 30.

[0135] Comparing the second configuration example of the coupled line 21-i shown in FIG. 8 with the third configuration example of the coupled line 21-i shown in FIG. 9, both coupled lines 21-i have in common the fact that they have two video wirings 32-1, 32-2 and two guidance wirings 33-1, 33-2 that are formed in parallel on the surface of the dielectric 30.

[0136] In contrast, the third configuration example of the coupled line 21-i differs from the second configuration example of the coupled line 21-i in that the guiding wire 33-1 is formed next to the video wire 32-1 and the guiding wire 33-2 is formed next to the video wire 32-2 in that the guiding wire 33-2 is formed next to the video wire 32-1 and the guiding wire 33-1 is formed next to the video wire 32-2. That is, in the third configuration example of the coupled line 21-i, the guiding wires 33-1 and 33-2 are formed so that the polarity of the guiding signal is inverted compared to the second configuration example.

[0137] The wiring distance between the two video wirings 32-1 and 32-2 that transmit the video signal is s V(i), the wiring interval between the video wiring 32-1 transmitting the video signal of the positive side differential signal P and the guidance wiring 33-2 transmitting the induced signal of the negative side differential signal N is defined as p2(i). Also, the wiring interval between the video wiring 32-2 transmitting the video signal of the negative side differential signal N and the guidance wiring 33-1 transmitting the induced signal of the positive side differential signal P is defined as p1(i). Other wiring widths w V The parameters such as (i) are assumed to be the same as those shown in FIG.

[0138] In the coupled line 21-i, the jitter J(i) that the induced signal flowing through the induced wirings 33-1 and 33-2 gives to the video wirings 32-1 and 32-2 is determined by the above-mentioned wiring interval s V It is expressed by the above formula (6) using parameters such as (i).

[0139] In the third configuration example of the coupled line 21-i, the polarity of the induced signal is inverted compared to the second configuration example, which inverts the sign of the crosstalk induced from the induced signal to the video signal, causing the jitter J(i) to fluctuate.

[0140] (Coupling line 21-i / fourth configuration example) Next, a detailed description will be given of a fourth configuration example of the coupled lines 21-1 to 21-N (coupled lines 21-i) shown in Fig. 3. Fig. 10 is a diagram for explaining the fourth configuration example of the coupled line 21-i, in which the polarity of the induced signal is inverted compared to the first configuration example of the coupled line 21-i shown in Fig. 3.

[0141] Similar to the first configuration example shown in FIG. 3, this coupling line 21-i is configured to include a dielectric 30, a GND layer 31 laminated on the dielectric 30, and video wiring 32-1, 32-2 and guidance wiring 33-1, 33-2 that are arranged on the opposite side of the dielectric 30 from the GND layer 31 and are formed parallel to the surface of the dielectric 30.

[0142] Comparing the first configuration example of the coupled line 21-i shown in FIG. 3 with the fourth configuration example of the coupled line 21-i shown in FIG. 10, both coupled lines 21-i have in common the fact that they have two video wirings 32-1, 32-2 and two guidance wirings 33-1, 33-2 that are formed in parallel on the surface of the dielectric 30.

[0143] In contrast, the fourth configuration example of the coupled line 21-i differs from the first configuration example of the coupled line 21-i in that the guiding wire 33-2 is formed next to the video wires 32-1 and 32-2 and the guiding wire 33-1 is formed next to the guiding wire 33-2 in that the guiding wire 33-1 is formed next to the video wires 32-1 and 32-2 and the guiding wire 33-2 is formed next to the guiding wire 33-1. That is, in the fourth configuration example of the coupled line 21-i, the guiding wires 33-1 and 33-2 are formed so that the polarity of the guiding signal is inverted compared to the first configuration example.

[0144] In the coupled line 21-i, the jitter J(i) that the induced signal flowing through the induced wirings 33-1 and 33-2 gives to the video wirings 32-1 and 32-2 is determined by the above-mentioned wiring interval s V It is expressed by the above formula (1) using parameters such as (i).

[0145] In the fourth configuration example of the coupled line 21-i, the polarity of the induced signal is inverted compared to the first configuration example, which inverts the sign of the crosstalk induced from the induced signal to the video signal, causing the jitter J(i) to fluctuate.

[0146] (Coupling line 21-i / Fifth configuration example) Next, a fifth configuration example of the coupled lines 21-1 to 21-N (coupled lines 21-i) shown in Fig. 3 will be described in detail. Fig. 11 is a cross-sectional view for explaining the fifth configuration example of the coupled line 21-i, showing a case where the video wiring 32-1, 32-2 and the guiding wiring 33-1, 33-2 are covered with a dielectric other than the dielectric 30. The coupled line 21-i in this case is an embedded type microstrip line.

[0147] This coupled line 21-i is composed of a dielectric 30-1, a GND layer 31 laminated on the dielectric 30-1, video wiring 32-1, 32-2 and guidance wiring 33-1, 33-2 arranged on the opposite side of the dielectric 30-1 from the GND layer 31 and formed parallel to the surface of the dielectric 30-1, and a dielectric 30-2.

[0148] Comparing the first configuration example of the coupled line 21-i shown in FIG. 3 with the fifth configuration example of the coupled line 21-i shown in FIG. 11, both coupled lines 21-i have in common the fact that they include a dielectric 30 (30-1), a GND layer 31, video wiring 32-1, 32-2, and guidance wiring 33-1, 33-2.

[0149] In contrast, the fifth configuration example of the coupled line 21-i includes a dielectric 30-2 in addition to the dielectric 30-1, which is different from the first configuration example of the coupled line 21-i that does not include the dielectric 30-2. That is, in the first configuration example of the coupled line 21-i, the video wiring 32-1, 32-2 and the guiding wiring 33-1, 33-2 are formed at the boundary between the dielectric 30 and the air, but in the fifth configuration example of the coupled line 21-i, the video wiring 32-1, 32-2 and the guiding wiring 33-1, 33-2 are formed at the boundary between the dielectric 30-1 and the dielectric 30-2.

[0150] In the fifth configuration example of the coupled line 21-i, the dielectric 30-2 is laminated on the dielectric 30-1 and is arranged so as to cover the two guidance wires 33-1 and 33-2 and the two video wires 32-1 and 32-2.

[0151] The height of the dielectric 30-1 is h1(i), and the relative dielectric constant of the dielectric 30-1 is ε r1 (i), the height of the dielectric 30-2 is h2(i), and the relative dielectric constant of the dielectric 30-2 is ε r2 (i) Other wiring intervals s V The parameters such as (i) are assumed to be the same as those in the first configuration example shown in FIG.

[0152] In the coupled line 21-i, the jitter J(i) that the induced signal flowing through the induced wirings 33-1 and 33-2 gives to the video wirings 32-1 and 32-2 is determined by the above-mentioned wiring interval s V Using parameters such as (i), it is expressed by the following function g(·). [Number 7] J(i) = g(s V (i), p(i), s A (i),w V (i),w A (i), L(i), h1(i), h2(i), ε r1 (i),ε r2 (i),f(i)) (7)

[0153] In the above formula (7), by providing the dielectric 30-2, the jitter J(i) becomes smaller than when the dielectric 30-2 is not provided. This is because the degree of coupling changes compared to the case of air depending on how the electric field lines pass through the dielectric 30-2.

[0154] [Error tolerance evaluation device] Next, a description will be given of an error tolerance evaluation device including the signal generating device 1 shown in Fig. 1. Fig. 12 is a schematic diagram showing an example of the configuration of an entire system for evaluating error tolerance to periodic jitter.

[0155] This system is configured to include an error resilience evaluation device 3 and an external device 4 in order to evaluate the error resilience of the external device 4 against periodic jitter. The error resilience evaluation device 3 includes a signal generating device 1, a video signal input circuit 40, a video signal receiving circuit 41, and an error measuring circuit .

[0156] The error robustness evaluation device 3 may include the signal generating device 2 shown in FIG.

[0157] The signal generator 1 of the error tolerance evaluation device 3 receives the element number i from the error measurement circuit 42, and generates a video signal VS1 with jitter J(i) added thereto using the coupled line 21-i. The signal generator 1 then outputs the video signal VS1 with jitter J(i) added thereto to the external device 4, and also outputs the video signal VS1 to the error measurement circuit 42.

[0158] Incidentally, the signal generating device 1 may output a pseudo-random signal or a clock signal to which jitter J(i) has been added, instead of the video signal VS1 to which jitter J(i) has been added.

[0159] The external device 4 is a device such as a routing switcher equipped with a crosspoint switch for switching between input and output paths of signals. The external device 4 receives the video signal VS1 to which jitter J(i) has been added from the signal generating device 1.

[0160] In the external device 4, a bit error occurs in the data of the video signal VS1 due to the jitter J(i) added to the video signal VS1. The external device 4 outputs the video signal including the generated bit error to the video signal input circuit 40 of the error tolerance evaluation device 3. As a result, a video signal reflecting the jitter characteristics of the external device 4 is output from the external device 4.

[0161] The video signal input circuit 40 inputs a video signal including a bit error from an external device 4, processes the video signal using a specified input interface, and outputs the video signal that has been processed using the specified input interface to a video signal receiving circuit 41.

[0162] The video signal receiving circuit 41 is a circuit corresponding to the video signal transmitting circuit 10 of the signal generating device 1 shown in Fig. 1. The video signal receiving circuit 41 receives a video signal from the video signal input circuit 40, performs a predetermined process, and outputs a video signal VS2 that has been subjected to the predetermined process (video signal VS2 including a bit error) to the error measuring circuit 42.

[0163] The error measurement circuit 42 outputs the element number i to the signal generator 1, and inputs from the signal generator 1 the video signal VS1 to which jitter J(i) corresponding to the element number i has been added. The error measurement circuit 42 also inputs from the video signal receiving circuit 41 the video signal VS2 containing bit errors caused by the jitter J(i) corresponding to the element number i. The error measurement circuit 42 then measures the BER (Bit Error Rate) based on the video signals VS1 and VS2. The error measurement circuit 42 performs this process for each element number i.

[0164] 13 is a flowchart showing an example of processing by the error measurement circuit 42. The error measurement circuit 42 sets element number i to 1 (step S1301), and outputs element number i to the signal generating device 1 (step S1302).

[0165] The error measuring circuit 42 inputs from the signal generating device 1 the video signal VS1 to which jitter J(i) corresponding to element number i has been added, and also inputs from the video signal receiving circuit 41 the video signal VS2 including a bit error caused by the jitter J(i) corresponding to element number i (step S1303).

[0166] The error measurement circuit 42 measures the BER corresponding to the element number i by counting the number of bits that differ between the data of the video signal VS1 and the data of the video signal VS2 (step S1304).

[0167] In this example, the amount of jitter J(i) corresponding to element number i is assumed to increase monotonically as element number i increases. In other words, the frequency f(i) of the induced signal and the wiring interval s are adjusted so that the amount of jitter J(i) increases as element number i increases. V The parameters such as (i) are determined, and the transmission line 13 of the signal generator 1 has a wiring interval s V It is assumed that the coupled line 21-i reflects parameters such as (i).

[0168] The error measurement circuit 42 judges whether the BER is smaller than a preset threshold value (step S1305). If the error measurement circuit 42 judges in step S1305 that the BER is smaller than the threshold value (step S1305: Y), the process proceeds to step S1306. On the other hand, if the error measurement circuit 42 judges in step S1305 that the BER is not smaller than the threshold value (step S1305: N), the process proceeds to step S1308.

[0169] The error measurement circuit 42 proceeds from step S1305 (Y) and judges whether or not the element number i is equal to or greater than the preset number of elements N (step S1306). If the error measurement circuit 42 judges in step S1306 that the element number i is not equal to or greater than the number of elements N (step S1306: N), it adds 1 to the element number i (step S1307) and proceeds to step S1302. As a result, the processes of steps S1302 to S1305 are performed for the new element number i.

[0170] On the other hand, if the error measurement circuit 42 determines in step S1306 that the element number i is equal to or greater than the number of elements N (step S1306: Y), the error measurement circuit 42 proceeds to step S1308.

[0171] Proceeding from step S1305(N) or step S1306(Y), the error measurement circuit 42 outputs the relationship between the BER measured in step S1304 and the amount of jitter J(i) preset corresponding to element number i as data in a graph display, table format, or the like (step S1308).

[0172] Incidentally, the error measurement circuit 42 may measure a CRC (Cyclic Redundancy Check) error rate instead of the BER, and output the relationship between the CRC error rate and the amount of jitter J(i) as data.

[0173] Further, the error measurement circuit 42 may measure the number of bit errors or the number of CRC errors and output, as data, the relationship between the number of errors and the amount of jitter J(i).

[0174] As described above, according to the error tolerance evaluation apparatus 3 shown in FIG. 12, a user can quantitatively confirm the tolerance to periodic jitter for an external apparatus 4 that inputs, for example, a U-SDI signal, while looking at indexes such as video, BER, and CRC error rate.

[0175] Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the technical idea thereof.

[0176] For example, regarding the coupling line 21-i, the first configuration example shown in FIG. 3, the second configuration example shown in FIG. 8, the third configuration example shown in FIG. 9, the fourth configuration example shown in FIG. 10, and the fifth configuration example shown in FIG. 11 are merely examples, and the present invention is not limited to these configuration examples. Further, the arrangement of the four video wirings 32-1 and 32-2 and the induction wirings 33-1 and 33-2 formed on the surfaces of the dielectrics 30 and 30-1 may be arbitrary.

[0177] Also, in the signal generation apparatus 1 shown in FIG. 1 and the signal generation apparatus 2 shown in FIG. 4, an example of adding jitter to a video signal is shown, but the present invention is also applicable when adding jitter to a signal other than a video signal.

Description of Reference Numerals

[0178] 1, 2 Signal generation apparatus 3 Error tolerance evaluation apparatus 4 External apparatus 10, 10-1 to 10-M Video signal transmission circuit 11, 11-1 to 11-M Inductive signal transmission circuit 12 Jitter characteristic control circuit 13, 13-1 to 13-M Transmission line (jitter addition circuit) 14, 14-1 to 14-M Video signal output circuit 15,15-1~15-M Induction signal output circuit 20, 20-1 to 20-M, 22, 22-1 to 22-M switching circuit 21-1~21-N,21-1-1~21-1-M,...,21-N-1~21-NM coupled line 30, 30-1, 30-2 Dielectric 31 GND (ground) layer 32-1, 32-2 Video wiring 33-1,33-2 Induction wiring 40 Video signal input circuit 41 Video signal receiving circuit 42 Error measurement circuit i Element number N Number of elements M Number of links m Link number s V Spacing between two video cables p, p1, p2 Wiring spacing between video wiring and guidance wiring s A Spacing between two induction wires w V Wiring width for video wiring w A Guiding wire width L Wiring length h,h1,h2 Height of dielectric ε r ,ε r1 ,ε r2 Dielectric constant f is the frequency of the induced signal (the frequency of the periodic jitter) VS1, VS2 video signal

Claims

1. 1. An error resilience evaluation apparatus for evaluating an error resilience of an external device against jitter using a signal to which jitter has been added, comprising: a signal generator for generating the jittered signal; an error measurement circuit for measuring an error indicating a BER (bit error rate), a number of bit errors, a CRC (cyclic redundancy check) error rate, or a number of CRC errors by comparing the signal generated by the signal generating device with a signal including bit errors generated in response to input of the signal in the external device; The signal generating device comprises: a signal transmission circuit for transmitting a differential signal through two signal lines; an induced signal transmitting circuit that generates a differential induced signal by two periodic signal lines reflecting a predetermined frequency f and transmits the induced signal; a transmission line having a plurality of coupled lines, any one of the plurality of coupled lines being designated; Each of the plurality of coupled lines is A dielectric body, and two signal wires and two induction wires formed in parallel on a surface of the dielectric body, The wiring interval between the two signal wirings is s V , the wiring interval between the adjacent signal wiring and the guiding wiring is p, and the wiring interval between the two guiding wirings is s A , the wiring width of the signal wiring is w V The width of the guiding wire is w A , the wiring length of the two signal wirings and the two guidance wirings is L, the height of the dielectric is h, and the relative dielectric constant of the dielectric is ε r It is configured as the signal transmitted by the signal transmitting circuit is transmitted through the two signal wirings, and the induced signal transmitted by the induced signal transmitting circuit is transmitted through the two induced wirings, thereby adding the jitter to the signal due to crosstalk from the induced signal to the signal; The jitter is The frequency f and the wiring interval s V , p, s A , the wiring width w V , w A , the wiring length L, the height h, and the relative dielectric constant ε r is determined by The error measurement circuit includes: performing an output process of outputting an element number i (i is an integer satisfying 1≦i≦N (N is the number of the plurality of coupled lines)) for designating any one of the plurality of coupled lines in the transmission line provided in the signal generating device to the signal generating device, thereby generating a signal to which the jitter corresponding to the element number i has been added for the signal generating device; an input process of inputting, from the signal generating device, a signal to which the jitter corresponding to the element number i has been added as a first signal, and inputting, from the external device, a signal including a bit error generated in association with the input of the first signal in the external device as a second signal, and a measurement process of measuring the error by comparing the first signal with the second signal, As the element number i increases, the amount of jitter increases monotonically. an error tolerance evaluation device that, starting from element number i=1, when the value of the error is smaller than a preset threshold, repeats a process of adding 1 to element number i, the output process, the input process, and the measurement process, thereby determining a relationship between the error measured in the measurement process and the jitter.

2. 1. An error resilience evaluation device for evaluating an error resilience of an external device against jitter using a multi-link signal having a plurality of links, the multi-link signal having jitter added thereto, a signal generator for generating a multilink signal to which the jitter has been added; an error measurement circuit for measuring an error indicating a BER (bit error rate), the number of bit errors, a CRC (cyclic redundancy check) error rate, or the number of CRC errors by comparing the signal generated by the signal generating device with a multi-link signal including a bit error generated in response to input of the signal in the external device; The signal generating device comprises: A signal transmitting circuit, an induction signal transmitting circuit, and a transmission line are provided for each of the plurality of links; The signal transmission circuit includes: Generate a differential signal using two signal lines, The induction signal transmitting circuit includes: A predetermined frequency f is designated, and a differential induced signal is generated by two periodic signal lines reflecting the frequency f, and the induced signal is transmitted; The transmission line is A plurality of coupled lines are provided, and one of the plurality of coupled lines is designated; Each of the plurality of coupled lines is A dielectric body, and two signal wires and two induction wires formed in parallel on a surface of the dielectric body, Let the wiring interval between the two signal wirings be s V , the wiring interval between the adjacent signal wiring and the induction wiring be p, and the wiring interval between the two induction wirings be s A , the wiring width of the signal wiring be w V , the wiring width of the induction wiring be w A , the wiring length of the two signal wirings and the two induction wirings be L, the height of the dielectric be h, and the relative permittivity of the dielectric be ε r and is configured as the signal transmitted by the signal transmitting circuit is transmitted through the two signal wirings, and the induced signal transmitted by the induced signal transmitting circuit is transmitted through the two induced wirings, thereby adding the jitter to the signal due to crosstalk from the induced signal to the signal; The jitter is The frequency f and the wiring interval s V , p, s A , the wiring width w V , w A , the wiring length L, the height h, and the relative dielectric constant ε r is determined by The error measurement circuit includes: performing an output process of outputting to the signal generating device an element number i (i is an integer satisfying 1≦i≦N (N is the number of the plurality of coupled lines)) for designating one of the plurality of coupled lines in the transmission line provided in the signal generating device, thereby generating a multi-link signal to which the jitter corresponding to the element number i has been added for the signal generating device; an input process of inputting, from the signal generating device, a multi-link signal to which the jitter corresponding to the element number i has been added as a first signal, and inputting, from the external device, a multi-link signal including a bit error generated in association with the input of the first signal in the external device as a second signal, and a measurement process of measuring the error by comparing the first signal with the second signal, As the element number i increases, the amount of jitter increases monotonically. an error tolerance evaluation device that, starting from element number i=1, when the value of the error is smaller than a preset threshold, repeats a process of adding 1 to element number i, the output process, the input process, and the measurement process, thereby determining a relationship between the error measured in the measurement process and the jitter.

3. 3. The error tolerance evaluation device according to claim 1, Each of the plurality of coupled lines in the transmission line provided in the signal generating device comprises: an error tolerance evaluation device comprising: the dielectric; the two signal wirings formed in parallel on a surface of the dielectric; and the two guiding wirings formed adjacent to the two signal wirings.

4. 3. The error tolerance evaluation device according to claim 1, Each of the plurality of coupled lines in the transmission line provided in the signal generating device comprises: the dielectric, the two signal wires formed in parallel on a surface of the dielectric, and the two guiding wires formed to sandwich the two signal wires, The wiring interval between the two signal wirings is s V The wiring interval between the wiring that transmits the induced signal on the positive side of the two guiding wirings and one of the two signal wirings is p1, the wiring interval between the wiring that transmits the induced signal on the negative side of the two guiding wirings and the other of the two signal wirings is p2, and the wiring width of the signal wiring is w V The width of the guiding wire is w A , the wiring length of the two signal wirings and the two guidance wirings is L, the height of the dielectric is h, and the relative dielectric constant of the dielectric is ε r It is configured as the signal transmitted by the signal transmitting circuit is transmitted through the two signal wirings, and the induced signal transmitted by the induced signal transmitting circuit is transmitted through the two induced wirings, thereby adding the jitter to the signal due to crosstalk from the induced signal to the signal; The jitter is The frequency f and the wiring interval s V , p1, p2, the wiring width w V , w A , the wiring length L, the height h, and the relative dielectric constant ε r The error resilience evaluation device according to claim 1, wherein the error resilience is determined by the following equation.

5. 3. The error tolerance evaluation device according to claim 1, Each of the plurality of coupled lines in the transmission line provided in the signal generating device comprises: the dielectric; the two signal wires and the two guiding wires formed in parallel on a surface of the dielectric; and a second dielectric laminated on the dielectric and disposed so as to cover the two signal wires and the two guiding wires; The wiring interval between the two signal wirings is s V , the wiring interval between the adjacent signal wiring and the guiding wiring is p, and the wiring interval between the two guiding wirings is s A , the wiring width of the signal wiring is w V The width of the guiding wire is w A , the wiring length of the two signal wirings and the two guidance wirings is L, the height of the dielectric is h1, and the relative dielectric constant of the dielectric is ε r1 , the height of the second dielectric is h2, and the relative dielectric constant of the second dielectric is ε r2 It is configured as the signal transmitted by the signal transmitting circuit is transmitted through the two signal wirings, and the induced signal transmitted by the induced signal transmitting circuit is transmitted through the two induced wirings, thereby adding the jitter to the signal due to crosstalk from the induced signal to the signal; The jitter is The frequency f and the wiring interval s V , p, s A , the wiring width w V , w A , the wiring length L, the heights h1 and h2, and the relative dielectric constant ε r1 , ε r2 The error resilience evaluation device according to claim 1, wherein the error resilience is determined by the following equation.

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