Dual-band instrument communication for achieving high bandwidth and low latency

Abstract

Dual band instrument communications for achieving high bandwidth and low latency are disclosed. Systems and methods enable communication between test and measurement instruments. A first test and measurement instrument and a second test and measurement instrument may be included in a test and measurement system. A dual band communication link is coupled between the first test and measurement instrument and the second test and measurement instrument. The dual band communication link includes a high bandwidth communication link having a first delay to communicate test data between the first test and measurement instrument and the second test and measurement instrument. The dual band communication link also includes a low latency communication link independent of the high bandwidth communication link. The low latency communication link has a second latency less than the first latency to communicate control commands between the first test and measurement instrument and the second test and measurement instrument.

Description

[0001] Cross - Reference to Related Applications

[0002] This disclosure claims priority to U.S. Provisional Patent Application No. 63 / 616,420, filed on December 29, 2023, entitled "DUAL - BAND INSTRUMENT COMMUNICATION TO ACHIEVE HIGH BANDWIDTH AND LOW LATENCY", the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure generally relates to communication with test and measurement instruments, and more particularly, to a dual - band communication link including separate low - latency and high - bandwidth communication links for transmitting control commands and acquired test data to and from test and measurement instruments. Background Art

[0004] A test and measurement system may include multiple test and measurement instruments for acquiring test data from a device under test (DUT). In such a test and measurement system, one of the test and measurement instruments typically acts as a master or main test and measurement controller. Other test and measurement instruments are coupled to the main test and measurement instrument via a communication link to transfer the test data acquired from the DUT to the main test and measurement instrument. The main test and measurement instrument includes a user interface that enables a user to analyze the acquired test data received from other test and measurement instruments via the communication link. The user interface also enables the user to provide control commands via the communication link to control the operation of other test and measurement instruments.

[0005] In such a test and measurement system, the test data acquired by other test and measurement instruments corresponds to the acquired waveforms of one or more signals of the DUT. These acquired waveforms may be very large files including gigabytes of test data. The large file size of the acquired waveforms makes the communication link between other test and measurement instruments and the main test and measurement instrument a high - bandwidth communication link. Such high bandwidth is required to transfer the acquired waveforms to the main test and measurement instrument in a timely manner.

[0006] In addition to providing high bandwidth for the transfer of test data, a communication link must also provide low-latency communication. Low latency is required so that a main test and measurement instrument can provide control commands that control the operation of other test and measurement instruments. For example, low latency is required in cases where the system includes multiple other test and measurement instruments that are operated in a collaborative manner to jointly acquire test signals from a DUT. Such a situation may occur in a production scenario where the DUT is tested as part of a production process. In such a case, the reconfiguration or collaborative control of the multiple other test and measurement instruments by the main test and measurement instrument ideally occurs as quickly as possible to maximize the throughput of the test and measurement system and the output of the production process. Latency and bandwidth are separate parameters of a communication link, and a high-bandwidth communication link may not have low latency. This also holds true for a low-latency communication link, which may not have high bandwidth. For example, a high-bandwidth communication link such as a Peripheral Component Interconnect Express (PCIe) bus uses a protocol that includes relatively large headers for the packets of data being transmitted. These large packet headers result in relatively high latency for the PCIe bus. Accordingly, there is a need for an improved communication link that provides both high bandwidth and low latency for use in a test and measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a block diagram of a test and measurement system according to an embodiment of the present disclosure, the test and measurement system including a main test and measurement instrument that is coupled to an auxiliary test and measurement instrument via a dual-band communication link that provides high-bandwidth transfer of test data and low-latency communication of control commands.

[0008] Figure 2 is a more detailed illustration according to an embodiment of the present disclosure Figure 1 of the dual-band communication link.

[0009] Figure 3 is a more detailed illustration according to a further embodiment of the present disclosure Figure 1 of the dual-band communication link.

[0010] Figure 4 is an illustration according to an embodiment of the present disclosure Figure 2 or Figure 3 of a communication layer implemented in a main instrument controller and an auxiliary instrument controller.

[0011] Figure 5 is a flowchart of a process that can be implemented in a test and measurement system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0012] Embodiments of the present disclosure are directed to a test and measurement system that includes a dual-band communication link for transferring a large amount of acquired test data over a high-bandwidth communication link and for transferring control commands over a low-latency communication link to control test and measurement instruments being utilized in the system. According to some embodiments of the present disclosure, the test and measurement system includes a main test and measurement instrument or a first test and measurement instrument and an auxiliary test and measurement instrument or a second test and measurement instrument. The dual-band communication link is coupled between the first test and measurement instrument and the second test and measurement instrument. The dual-band communication link includes a high-bandwidth communication link having a first latency for transmitting test data between the first test and measurement instrument and the second test and measurement instrument. The dual-band communication link further includes a low-latency communication link independent of the high-bandwidth communication link. The low-latency communication link has a second latency less than the first latency for transmitting control commands between the first test and measurement instrument and the second test and measurement instrument.

[0013] The dual-band communication link provides the high bandwidth required to perform timely transfer of a large amount of test data acquired by the second test and measurement instrument to the first test and measurement instrument. In addition, through the separate low-latency communication link, the dual-band communication link enables the second test and measurement instrument to be reconfigured in a timely manner by the first test and measurement instrument. The test and measurement system may also include additional test and measurement instruments, and the low-latency communication link enables these other test and measurement instruments to be reconfigured and collaboratively controlled in a timely manner by the first test and measurement instrument or the main test and measurement instrument. This control desirably occurs as quickly as possible to maximize the throughput of the test and measurement system in testing a device under test (DUT).

[0014] In a test and measurement system according to an embodiment of the present disclosure, instead of the test and measurement instrument manufacturer designing a new and custom high-bandwidth communication link, a third-party or off-the-shelf intellectual property (IP) core may be used. A core is a reusable logic block or integrated circuit layout design that has been designed by another party and that may be licensed for use in the component or system being designed. The IP of the core defines the functionality of the core, where the IP core is typically implemented through a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). For example, in an embodiment of the present disclosure, the high-bandwidth communication link may be implemented through a third-party IP core that includes a peripheral component interconnect high-speed (PCIe) bus core and a direct memory access (DMA) core.

[0015] This use of third-party IP cores reduces the time and cost of the high-bandwidth communication links required for the design and the overall test and measurement system for manufacturers of test and measurement instruments. In an embodiment of the present disclosure, the low-latency communication link may be a custom or proprietary communication link that implements a low-overhead communication protocol to reduce the latency of the link. The low-latency communication link may be a standard low-overhead protocol communication link in other embodiments, such as a serial communication link including a universal asynchronous receiver-transmitter (UART) or a serial communication link including a serial peripheral interface (SPI).

[0016] Figure 1 FIG. 4 is a block diagram of a test and measurement system 100 according to an embodiment of the present disclosure, including a main test and measurement instrument 102 coupled to an auxiliary test and measurement instrument 104 via a dual-band communication link DBCL. The dual-band communication link DBCL provides high-bandwidth transmission of test data acquired by the auxiliary test and measurement instrument 104, and also enables the main test and measurement instrument 102 to provide control commands to the auxiliary test and measurement instrument 104 with low latency (LL). The terms "low latency" and "low-latency" may be abbreviated as "LL" in this description and the accompanying figures. An instrument controller 106 in the test and measurement instrument 102 and an instrument controller 108 in the test and measurement instrument 104 communicate via the dual-band communication link DBCL. The instrument controllers 106 and 108 are part of the dual-band communication link DBCL, and the structure and operation of these instrument controllers are described in more detail below with reference to Figure 2 and Figure 3 FIGS. 5 and 6.

[0017] The dual-band communication link DBCL includes a high-bandwidth communication link HBCL to transmit test data acquired by the auxiliary test and measurement instrument 104 to the main test and measurement instrument 102. The low-latency communication link LLCL in the dual-band communication link DBCL provides low-latency communication of control commands from the main test and measurement instrument 102 to the auxiliary test and measurement instrument 104 to reconfigure or otherwise control the operation of the auxiliary test and measurement instrument 104. In this description, each of the main test and measurement instrument 102 and the auxiliary test and measurement instrument 104 may be alternately referred to as the first test and measurement instrument and the second test and measurement instrument, respectively, or simply as instrument 102 or instrument 104.

[0018] The test and measurement instrument 102 includes one or more processors 110, which may be configured to execute instructions from the memory 112 and may perform any method and / or associated steps corresponding to such instructions. The user interface 114 is coupled to the one or more processors 110 and may include, for example, a keyboard, a mouse, a touch screen, an output display, a file storage, and / or any other controls that can be employed by a user to interact with the instrument 102. In some embodiments, the user interface 114 may be connected to or controlled by a remote interface (not shown), such that a user can control the operation of the instrument 102 from a remote location physically distant from the instrument. The display portion of the user interface 114 may be a digital screen, such as an LCD, an LED, or any other monitor, to display waveforms, measurements, and other data to the user. In some embodiments, the main output display of the user interface 114 may also be positioned remotely from the instrument 102.

[0019] The test and measurement instrument 102 further includes one or more measurement units 116, which perform the function of measuring parameters and other qualities of signals from the DUT that is being measured or tested by the instrument 102. Typical measurements include measuring the voltage, current, and power of a signal in the time domain and the characteristics of a signal in the frequency domain. The measurement unit 116 represents any measurement performed on the test and measurement instrument, and the instrument controller 106 may be coupled to or integrated within the measurement unit 116 or other components of the instrument 102. The test and measurement instrument 104 similarly includes a processor 118, a memory 120, a user interface 122, and a measurement unit 124, each of which functions in the same manner as the corresponding components described above with respect to the test and measurement instrument 102.

[0020] As mentioned above, the size of the collected test data may be very large, including thousands of gigabytes of test data, and the high-bandwidth communication link HBCL has the bandwidth required for the timely transfer of this test data from the auxiliary test and measurement instrument 104 to the main test and measurement instrument 102. For example, in some embodiments of the present disclosure, the high-bandwidth communication link HBCL is a peripheral component interconnect express (PCIe) bus that provides a very high bandwidth for transferring test data over the high-bandwidth communication link HBCL. For example, in the case where the PCIe bus is version PCIe 6.0 and the PCIe bus may include up to thirty-two (32) lanes, the term "high bandwidth" as used in this context may be communication at a rate of 64 GT / s (GT = gigatransfers per second) over each lane. In further embodiments of the test and measurement system 100, the high-bandwidth communication link HBCL may be other types of high-bandwidth communication links that implement other protocols, such as the Ethernet protocol or the universal serial bus (USB) protocol.

[0021] In addition to its high-bandwidth nature, the High-Bandwidth Communication Link (HBCL) also needs to communicate via a highly efficient protocol, meaning that a large percentage of each transmitted message segment is reserved for data being sent between the auxiliary test and measurement instrument 104 and the main test and measurement instrument 102.

[0022] Although having an efficient high-bandwidth communication protocol, the latency between messages of the High-Bandwidth Communication Link (HBCL) may be too large to permit the desired control of the auxiliary test and measurement instrument 104 by the main test and measurement instrument 102. Additionally, even if the latency of the High-Bandwidth Communication Link (HBCL) is low enough, transmitting a large amount of the acquired test data from the auxiliary test and measurement instrument 104 using the High-Bandwidth Communication Link (HBCL) may mean that the High-Bandwidth Communication Link (HBCL) is either saturated - meaning the High-Bandwidth Communication Link (HBCL) is active 100% of the time to transmit the acquired test data, or the latency of the space in the data stream of the High-Bandwidth Communication Link (HBCL) where control commands can be placed is very high.

[0023] One approach for attempting to address the high-latency problem of high-bandwidth communication links in test and measurement systems is to design a custom high-bandwidth communication link with reduced latency. However, manufacturers of test and measurement instruments in the test and measurement industry may not have specialized expertise in designing high-bandwidth communication links. Additionally, fast time-to-market is increasingly becoming an important goal in the industry for new test and measurement system capabilities, meaning there is less time for the independent design of new components for such systems. Another approach for addressing the high-latency problem of high-bandwidth communication links is to modify or customize the communication protocol implemented via a third-party IP core to reduce the latency of the communication link implemented by the IP core. This approach is typically not a viable option. When using a third-party IP core (such as the PCIe bus mentioned above), the IP core typically cannot be modified because of the terms of the license agreement under which the IP core is licensed from the third party. To ensure compliance with these license provisions against modification, the software portion of the licensed third-party IP core is typically encrypted.

[0024] The dual-band communication link DBCL overcomes these problems by providing a low-latency communication link LLCL that is independent of the high-bandwidth communication link HBCL. This independence enables the main test and measurement instrument 102 to provide control commands to the auxiliary test and measurement instrument 104 whenever control of the desired operation of the auxiliary test and measurement instrument 104 is needed. In this way, the dual-band communication link DBCL meets the needs in a test and measurement system for both high-bandwidth communication for transferring large amounts of data and low latency for controlling the operation of test and measurement instruments in the system. Additionally, the dual-band communication link DBCL eliminates the need for a new custom-designed communication link. Instead, third-party IP cores can be used for the high-bandwidth communication link HBCL, enabling the manufacturer of the test and measurement system to combine IP cores from various suppliers and integrate these IP cores at a higher level to meet the new system technical requirements while also meeting the desired time-to-market or scheduling goals. In an embodiment of the present disclosure, the low-latency communication link LLCL can be a custom-designed communication link that utilizes a custom low-overhead communication protocol to achieve the desired low latency for the link. Alternatively, the low-latency communication link LLCL can implement a standard low-overhead protocol communication link, such as a serial communication link including a universal asynchronous receiver-transmitter (UART) or a serial communication link including a serial peripheral interface (SPI).

[0025] Generally, during operation of the dual-band communication link DBCL, the low-latency communication link LLCL does not remain active as continuously as the high-bandwidth communication link HBCL activity. The low-latency communication link LLCL allows the main test and measurement instrument 102 to issue control commands to the auxiliary test and measurement instrument 104, or allows for inversion as needed for a particular application. Such commands can be timed to segments of data transfer between the test and measurement instruments 102, 104 over the high-bandwidth communication link HBCL, or can occur asynchronously to that data. As long as commands can always be issued as needed, additional data can also be transferred over the low-latency communication link LLCL for use by either instrument.

[0026] In some embodiments, each of the high - bandwidth communication link (HBCL) and the low - latency communication link (LLCL) provides two - way communication between the primary test and measurement instrument 102 and the secondary test and measurement instrument 104. Additionally, in some embodiments, test data can be acquired by each of the first test and measurement instrument 102 and the second test and measurement instrument 104 and transferred via the high - bandwidth communication link (HBCL) to the other of the first test and measurement instrument 102 and the second test and measurement instrument 104. Similarly, control commands can be transferred via the low - latency communication link (LLCL) from each of the first test and measurement instrument 102 and the second test and measurement instrument 104 to the other of the first test and measurement instrument 102 and the second test and measurement 104. The two - way communication via each of the high - bandwidth communication link (HBCL) and the low - latency communication link (LLCL) enables test data and control commands to be transferred in both directions via these communication links. This two - way communication also enables any required communication associated with the protocols implemented on each of the communication links HBCL, LLCL, such as communication related to handshakes, error correction, or other features of the particular protocols being utilized. The low - latency communication link (LLCL) provides two - way communication between the first test and measurement instrument 102 and the second test and measurement instrument 104 in embodiments, where such two - way communication can include status information or communication in response to control commands being transferred from the second test and measurement instrument 104 to the first test and measurement instrument 102.

[0027] The transmission rate, bit rate, or baud rate of the high - bandwidth communication link (HBCL) is significantly higher than the bandwidth of the low - latency communication link (LLCL). In the low - latency communication link (LLCL), the total time for transmitting a packet that includes a message or command is small relative to the total time for including the message or command in a packet via the high - bandwidth communication link (HBCL). This operation of the low - latency communication link (LLCL) can be achieved by small packets, a fast transmission rate, or both, or by both small packets and a fast transmission rate. The "fast transmission rate" of the low - latency communication link (LLCL) is fast enough to achieve the required low latency for the low - latency communication link, but is significantly less than the transmission rate of the high - bandwidth communication link (HBCL), as described previously.

[0028] In further embodiments of the present disclosure, the test and measurement system 100 includes additional test and measurement instruments ( Figure 1 not shown in the figure), and the additional test and measurement instruments are coupled to the dual - band communication link (DBCL) to transfer test data acquired from each of these additional test and measurement instruments to the primary test and measurement instrument 102. Referring below to Figure 3Embodiments including multiple additional test and measurement instruments are described in more detail. In yet a further embodiment of the present disclosure, any test and measurement instrument coupled to the dual-band communication link DBCL can act as a primary test and measurement instrument or as a secondary test and measurement instrument. In yet another further embodiment of the present disclosure, the instrument controller of a test and measurement instrument can be coupled to yet another additional test and measurement instrument via an additional dual-band communication link. In summary, the test and measurement system 100 can have different topologies in further embodiments of the present disclosure, where the test and measurement instruments in these different topologies are interconnected via the dual-band communication link DBCL.

[0029] Figure 2 FIG. is a block diagram more particularly illustrating a dual-band communication link 200 according to an embodiment of the present disclosure. The dual-band communication link 200 corresponds to Figure 1 an embodiment of the dual-band communication link DBCL. The dual-band communication link 200 includes a primary instrument controller 202 and a secondary instrument controller 204, which are respectively included in a primary test and measurement instrument and a secondary test and measurement instrument ( Figure 2 not shown). The primary instrument controller 202 and the secondary instrument controller 204 are described in this description as parts of or included in the dual-band communication link 200 because parts or components of each of these instrument controllers 202, 204 are directed to implementing the dual-band communication link 200 as illustrated in Figure 2 . However, in embodiments of the present disclosure, these instrument controllers 202, 204 can be considered separate from the dual-band communication link 200 and not included in the dual-band communication link 200. The dual-band communication link 200 includes a high-bandwidth communication link 206 and a low-latency communication link 208, which are coupled between the primary instrument controller 202 and the secondary instrument controller 204. The high-bandwidth communication link 206 and the low-latency communication link 208 include respective physical links PL-HB and PL-LL, and each of the physical links PL-HB and PL-LL represents a physical communication medium for the corresponding communication link, such as conductive wiring or an optical cable.

[0030] The high-bandwidth communication link 206 includes a high-bandwidth communication core 210, which is coupled to a first end of the physical link PL-HB and is configured to transmit and receive electrical signals via the physical link PL-HB to transfer test data. In Figure 2In an embodiment, the high-bandwidth communication core 210 is a PCIe core. The high-bandwidth data transfer core 212 in the main instrument controller 202 is coupled to the PCIe core 210 to receive test data from the PCIe core and store the test data in a memory (not shown) included in the main instrument controller 202. In Figure 2 In an embodiment, the high-bandwidth data transfer core 212 is a direct memory access (DMA) core, and each of the DMA core 212 and the PCIe core 210 is a third-party IP core.

[0031] The high-bandwidth communication link 206 includes corresponding IP core components at the other end of the physical link PL-HB coupled to the auxiliary instrument controller 204. More specifically, the high-bandwidth communication link 206 further includes a high-bandwidth communication core 214, which is coupled to the second end of the physical link PL-HB and is configured to transmit and receive electrical signals via the physical link PL-HB to transfer test data via the physical link PL-HB. In Figure 2 In an embodiment, the high-bandwidth communication core 214 is a PCIe core and is coupled to the high-bandwidth data transfer core 216 in the auxiliary instrument controller 204. The high-bandwidth data transfer core 216 receives test data from a memory (not shown) included in an auxiliary test and measurement instrument (not shown), and provides the received test data to the PCIe core 214, which in turn generates electrical signals to transfer the test data via the physical link PL-HB to the PCIe core 210. Again, in Figure 2 In an embodiment, the high-bandwidth data transfer core 216 is a direct memory access (DMA) core, and each of the DMA core 216 and the PCIe core 214 is a third-party IP core. In an embodiment of the present disclosure, each of the IP cores 210-216 may be implemented in a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC).

[0032] The low-latency communication link 208 includes a low-latency communication core 218, which is coupled to the first end of the physical link PL-LL and is configured to transmit and receive electrical signals via the physical link PL-LL to transfer control commands to control the operation of an auxiliary test and measurement instrument (not shown) including the auxiliary instrument controller 204. The low-latency communication core 218 is configured to receive control commands from the low-latency protocol core 220 and generate corresponding electrical signals to transfer the control commands via the physical link PL-LL to the auxiliary instrument controller 204. The low-latency communication core 218 may be, for example, a custom communication core designed to implement a low-overhead communication protocol. The test and measurement instrument including the main controller 202 and the auxiliary controller 204 ( Figure 2Manufacturers (not shown in

[0033] In Figure 2 an embodiment, the low-latency protocol kernel 220 is included in the main instrument controller 202 and is configured to receive control command instructions and generate control commands to be transmitted over the physical link PL-LL of the low-latency communication link 208. The main instrument controller 202 provides the control command instructions to the low-latency protocol kernel 220, and in response to the control command instructions, the low-latency protocol kernel generates control command packets using the low-overhead communication protocol of the low-latency communication link 208. The control command packets include the control commands to be transmitted from the main instrument controller 202 to the auxiliary instrument controller 204. The operation or configuration of the test and measurement instrument including the auxiliary instrument controller 204 ( Figure 2 not shown in

[0034] is adjusted by the applied control commands. In this way, the main instrument controller 202 supplies control command instructions to the low-latency protocol kernel 220 to control the operation of the auxiliary test and measurement instrument (not shown) including the auxiliary instrument controller 204. Figure 2 In an embodiment of the low-latency communication link 208, the low-latency communication kernels 218, 220 can be implemented in corresponding FPGAs. Each of the low-latency protocol kernels 220, 224 can also be implemented by an FPGA or by an ASIC. Further, although the operation of the low-latency communication link 208 is described as transmitting control commands from the main instrument controller 202 to the auxiliary instrument controller 204, in some embodiments of the present disclosure, other data or commands can be transmitted over this link.

[0035] The dual-band communication link 200 enables the main instrument controller 202 to identify or select which communication link (the high-bandwidth communication link 206 or the low-latency communication link 208) to use for communication with the auxiliary instrument controller 204. In operation, the main instrument controller 202 initially determines whether to perform communication via the high-bandwidth communication link 206 or the low-latency communication link 208. When a DMA transfer of test data is to be performed, the main instrument controller 202 determines that the high-bandwidth communication link 206 is to be used for communication. The DMA core 212, PCIe core 210, and DMA core 216, PCIe core 214 then operate in combination to transfer the test data stored in the auxiliary instrument controller 204 via the high-bandwidth communication link 206 and store the test data in the main instrument controller 202. Conversely, when reconfiguration or other control of the auxiliary instrument controller 204 is required, the main instrument controller 202 determines that the low-latency communication link 208 is to be used to send control commands to the auxiliary instrument controller 204. The LL protocol core 220, LL communication core 218, and LL protocol core 224, LL communication core 222 then operate in combination to apply the control commands to the auxiliary instrument controller 204 via the low-latency communication link 208, and the auxiliary instrument controller 204 in turn reconfigures or adjusts the control of the auxiliary test and measurement instrument in response to the control commands.

[0036] In this way, the two communication links 206, 208 can be used by the main instrument controller 202. In some embodiments of the present disclosure, the communication of test data and control commands can occur in both directions on the dual-band communication link 200, i.e., from the main instrument controller 202 to the auxiliary instrument controller 204 and from the auxiliary instrument controller to the main instrument controller. In such embodiments, each of the main instrument controller 202 and the auxiliary instrument controller 204 can determine which communication link 206, 208 in the dual-band communication link 200 to use in communicating with the other instrument controller. Further, in embodiments of the present disclosure, both of the communication links 206, 208 can operate simultaneously to transfer test data and control commands between the instrument controllers 202, 204.

[0037] Figure 3 is a block diagram that more particularly illustrates a dual-band communication link 300 in accordance with a further embodiment of the present disclosure. The dual-band communication link 300 corresponds to Figure 1Example of a dual-band communication link DBCL. The dual-band communication link 300 includes a main instrument controller 302, and the main instrument controller 302 is coupled to a plurality of auxiliary instrument controllers 304A, 304B via the dual-band communication link 300. More specifically, the dual-band communication link 300 includes a high-bandwidth communication link 306 and a low-latency communication link 308, and each of the high-bandwidth communication link 306 and the low-latency communication link 308 includes an intermediate switch to couple the plurality of auxiliary instrument controllers 304A, 304B to the main instrument controller 302. The high-bandwidth communication link 306 includes Figure 3 a PCIe bus in the embodiment of, and accordingly includes a DMA core and a PCIe core associated with each of the instrument controllers 302, 304A, 304B. Thus, the high-bandwidth communication link 306 includes a PCIe core 310 and a DMA core 312 on one end of the communication link coupled to the main instrument controller 302, and includes a PCIe core 314 and a DMA core 316 associated with the auxiliary instrument controller 304A and a PCIe core 318 and a DMA core 320 associated with the auxiliary instrument controller 304B at the opposite end of the communication link.

[0038] The intermediate switch 322 is Figure 3 a PCIe switch in the embodiment of, and is coupled to the main instrument controller 302 via a first physical link PL-HB1 of the high-bandwidth communication link 306. Each of the auxiliary instrument controllers 304A, 304B is coupled to the PCIe switch 322 via a respective physical link PL-HB2, PL-HB3. Additional auxiliary instrument controllers (not shown) can be coupled to the PCIe switch 322 via additional physical links, where Figure 3 two auxiliary instrument controllers 304A, 304B are illustrated by way of example in the embodiment of.

[0039] In operation, the main instrument controller 302 supplies commands to the PCIe switch 322 via the DMA core 312 and the PCIe core 310 to select one of the desired auxiliary instrument controllers 304A, 304B for communication. This selection effectively causes a high-bandwidth communication link to be formed between the main instrument controller 302 and one of the selected auxiliary instrument controllers 304A, 304B. The high-bandwidth communication link between the main instrument controller 302 and the selected auxiliary instrument controller 304A, 304B then operates as described above for Figure 2 the high-bandwidth communication link 206 of. Thus, the PCIe core 310, the DMA core 312, and the PCIe core 314, the DMA core 316 or the PCIe core 318, the DMA core 320 associated with the selected auxiliary instrument controller 304A or 304B operate in the same manner as described above for Figure 2The PCIe cores 210, DMA cores 212, PCIe cores 214, and DMA cores 216 in the high-bandwidth communication link 206 operate in the same manner as described.

[0040] The low-latency communication link 308 includes a low-latency communication core 324 and a low-latency (LL) protocol core 326 at one end of the low-latency communication link coupled to the main instrument controller 302, an LL communication core 328 and an LL protocol core 330 associated with the auxiliary instrument controller 304A, and an LL communication core 332 and an LL protocol core 334 associated with the auxiliary instrument controller 304B. The intermediate switch 336 is coupled to the main instrument controller 302 through a first physical link PL-LL1 of the low-latency communication link 308. Each of the auxiliary instrument controllers 304A, 304B is coupled to the intermediate switch 336 through a respective physical link PL-LL2, PL-LL3. Again, additional auxiliary instrument controllers (not shown) may be coupled to the intermediate switch 336 through additional physical links, where only two auxiliary instrument controllers 304A, 304B are illustrated by way of example.

[0041] In operation, the main instrument controller 302 supplies commands through the LL protocol core 326 and the LL communication core 324 to the intermediate switch 336 to select one of the desired auxiliary instrument controllers 304A, 304B for communication. This selection effectively causes a low-latency communication link to be formed between the main instrument controller 302 and one of the selected auxiliary instrument controllers 304A, 304B. The low-latency communication link between the main instrument controller 302 and the selected auxiliary instrument controller 304A, 304B then operates as described above for Figure 2 the low-latency communication link 208. Thus, the LL protocol core 326, the LL communication core 324, and the LL protocol core 330, communication core 328, or LL protocol core 334, LL communication core 332 associated with the selected auxiliary instrument controller 304A or 304B operate in the same manner as the LL protocol core 220, LL communication core 218, LL protocol core 224, and LL communication core 222 in the low-latency communication link 208 described above for Figure 2 the low-latency communication link 208.

[0042] Figure 4 is a diagram of a software layer 400 implemented between a main instrument controller 402 and an auxiliary instrument controller 404 coupled through a dual-band communication link DBCL according to an embodiment of the present disclosure. The main instrument controller 402 corresponds to Figure 2 and Figure 3 the main instrument controller 202 or 302 in the embodiments of Figure 2auxiliary instrument controller 204 or Figure 3 any one of auxiliary instrument controllers 304A, 304B. The main instrument controller 402 includes a library software layer 406, which may be an application programming interface (API) in an embodiment of the present disclosure and determines whether to use a high-bandwidth communication link HBCL or a low-latency communication link LLCL of the dual-band communication link DBCL for communication with the auxiliary instrument controller 404.

[0043] The library software layer 406 communicates with a higher layer of software (such as an application; not shown in Figure 4 ) executed on the main instrument controller 402 so that these software programs can treat the dual-band communication link DBCL as a single communication link providing communication with the auxiliary instrument controller 404. In operation, a software program (not shown) executed on the main instrument controller provides instructions for communication with the library software layer 406. The instructions include information that enables the library software layer 406 to determine whether the high-bandwidth communication link HBCL or the low-latency communication link LLCL is used for communication with the auxiliary instrument controller 404. The library software layer 406 then communicates with the high-bandwidth (HB) and low-latency (LL) layers 408, and the high-bandwidth (HB) and low-latency (LL) layers 408 in turn control the communication of the selected high-bandwidth or low-latency communication link HBCL, LLCL via the dual-band communication DBCL. The HB and LL layers 408 communicate with the corresponding IP cores of the dual-band communication link DBCL (such as Figure 2 ) PCIe core 210 and DMA core 212 or LL communication core 218 and LL protocol core 220) of to perform the desired communication via one of the selected high-bandwidth or low-latency communication links HBCL, LLCL. The auxiliary instrument controller 404 includes a library software layer 410 and HB and LL layers 412, and the library software layer 410 and HB and LL layers 412 operate in the same manner to facilitate communication with the main instrument controller 402 via the dual-band communication link DBCL.

[0044] Figure 5 is a flowchart of a process 500 that can be implemented in a test and measurement system according to an embodiment of the present disclosure. Now refer to Figure 2The dual-band communication link 200 describes a process 500. The process 500 begins at operation 502 and determines in a first test and measurement instrument (e.g., the primary test and measurement instrument 202) whether communication with a second test and measurement instrument (e.g., the secondary test and measurement instrument 204) is necessary. The process 500 then proceeds to operation 504 and determines in the first test and measurement instrument the type of appropriate communication. The type of communication is, for example, the transfer of test data from the second test and measurement instrument to the first test and measurement instrument or the application of a control command to the second test and measurement instrument. The process 500 then goes to operation 506 and selects in the first test and measurement instrument 202 one of a high-bandwidth communication link 206 and a low-latency communication link 208. The selection is based on the type of communication. The high-bandwidth communication link 206 has a first latency, and the low-latency communication link 208, independent of the high-bandwidth communication link 206, has a second latency that is less than the first latency.

[0045] From operation 506, the process 500 proceeds to operation 508, and the primary test and measurement instrument 202 communicates with the secondary test and measurement instrument 204 via the selected high-bandwidth communication link 206 or low-latency communication link 208. In an embodiment of the process 500, when the type of communication is the transfer of test data from the secondary test and measurement instrument 204 to the primary test and measurement instrument 202, the primary test and measurement instrument selects the high-bandwidth communication link 206 in operation 506 and performs communication with the secondary test and measurement instrument via the high-bandwidth communication link in operation 508. When the type of communication is the application of a control command to the secondary test and measurement instrument 204, the primary test and measurement instrument 202 selects the low-latency communication link 208 in operation 506 and performs communication with the secondary test and measurement instrument via the low-latency communication link in operation 508.

[0046] Aspects of the present disclosure may operate on specially created hardware, firmware, a digital signal processor, or on a specially programmed general-purpose computer including a processor operating according to programmed instructions. As used herein, the term “controller” or “processor” is intended to include a microprocessor, a microcomputer, an application specific integrated circuit (ASIC), and a dedicated hardware controller. One or more aspects of the present disclosure may be embodied in computer-usable data and computer-executable instructions, such as in one or more program modules, executed by one or more computers, including a monitoring module, or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., which perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The computer-executable instructions may be stored on a non-transitory computer-readable medium, such as on a hard disk, an optical disk, a removable storage medium, a solid state memory, a random access memory (RAM), etc. As will be appreciated by those skilled in the art, the functions of the program modules may be combined or distributed as desired in various aspects. In addition, the functionality may be embodied in whole or in part in firmware or hardware equivalents, such as in integrated circuits, field programmable gate arrays (FPGAs), etc. Particular data structures may be used to more effectively implement one or more aspects of the present disclosure, and such data structures are contemplated within the scope of the computer-executable instructions and computer-usable data described herein.

[0047] The disclosed aspects may in some cases be implemented in hardware, firmware, software, or any combination thereof. The disclosed aspects may also be implemented as instructions carried or stored on one or more non-transitory computer-readable media, which may be read and executed by one or more processors. Such instructions may be referred to as a computer program product. As discussed herein, a computer-readable medium means any medium that can be accessed by a computing device. By way of example and not limitation, a computer-readable medium may include computer storage media and communication media.

[0048] Computer storage media means any medium that can be used to store computer-readable information. By way of example and not limitation, computer storage media may include RAM, ROM, electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices, and any other volatile or non-volatile removable or non-removable media implemented in any technology. Computer storage media excludes signals themselves and transitory forms of signal transmissions.

[0049] A communication medium means any medium that can be used for communication of computer-readable information. By way of example and not limitation, a communication medium can include coaxial cables, fiber optic cables, air, or any other medium suitable for communication of electrical, optical, radio frequency (RF), infrared, acoustic, or other types of signals.

[0050] Example

[0051] Illustrative examples of the technology disclosed herein are provided below. Configurations of the technology can include any one or more of the examples described below and any combination thereof.

[0052] Example 1 is a test and measurement system including: a first test and measurement instrument; a second test and measurement instrument; and a dual-band communication link coupled between the first test and measurement instrument and the second test and measurement instrument, the dual-band communication link including a high-bandwidth communication link having a first latency for transmitting test data between the first test and measurement instrument and the second test and measurement instrument, and including a low-latency communication link independent of the high-bandwidth communication link, the low-latency communication link having a second latency less than the first latency for transmitting control commands between the first test and measurement instrument and the second test and measurement instrument.

[0053] Example 2 is the test and measurement instrument of Example 1, wherein the test and measurement system of Example 1 further includes: a first instrument controller in the first test and measurement instrument, the first instrument controller being configured to identify one of the high-bandwidth communication link and the low-latency communication link for communication with the second test and measurement instrument, and further being configured to initiate communication via the identified high-bandwidth communication link and low-latency communication link; and a second instrument controller in the second test and measurement instrument, the second instrument controller being configured to identify one of the high-bandwidth communication link and the low-latency communication link for communication with the first test and measurement instrument, and further being configured to initiate communication via the identified high-bandwidth communication link and low-latency communication link.

[0054] Example 3 is the test and measurement instrument of Example 2, wherein the first instrument controller is configured to: identify the high-bandwidth communication link for communication with the second test and measurement instrument when test data collected by the second test and measurement instrument is to be transmitted to the first test and measurement instrument; and wherein the second instrument controller is configured to: identify the high-bandwidth communication link for communication with the first test and measurement instrument when test data collected by the first test and measurement instrument is to be transmitted to the second test and measurement instrument.

[0055] Example 4 is the test and measurement instrument of Example 2, wherein the first instrument controller is configured to: identify a low-latency communication link for communication with the second test and measurement instrument when the first instrument controller determines that a control command is to be transmitted to the second test and measurement instrument.

[0056] Example 5 is the test and measurement instrument of Example 2, wherein the high-bandwidth communication link is one of the following: a Peripheral Component Interconnect Express (PCIe) communication link, a Universal Serial Bus (USB) communication link, and an Ethernet communication link.

[0057] Example 6 is the test and measurement instrument of Example 5, wherein the first instrument controller includes a Direct Memory Access (DMA) core, and the high-bandwidth communication link includes a PCIe core. The DMA core and the PCIe core are configured to operate in combination to transfer test data collected by the second test and measurement instrument via the PCIe communication link and store the test data in the first test and measurement instrument.

[0058] Example 7 is the test and measurement instrument of Example 2, wherein the low-latency communication link is one of the following: a serial communication link including a Universal Asynchronous Receiver-Transmitter (UART) or a serial communication link including a Serial Peripheral Interface (SPI).

[0059] Example 8 is the test and measurement instrument of Example 2, wherein the first instrument controller includes a low-latency protocol core, and the low-latency communication link includes a low-latency communication core. The low-latency protocol core and the low-latency communication core are configured to operate in combination to transfer a control command to the second test and measurement instrument via the low-latency communication link.

[0060] Example 9 is the test and measurement instrument of Example 8, wherein the low-latency communication link is one of the following: a Field Programmable Gate Array (FPGA) and an Application Specific Integrated Circuit (ASIC), and the Field Programmable Gate Array (FPGA) and the Application Specific Integrated Circuit (ASIC) are configured to implement the low-latency communication core.

[0061] Example 10 is the test and measurement instrument of Example 1, further including one or more additional test and measurement instruments, and the one or more additional test and measurement instruments are coupled to the first test and measurement instrument via a dual-band communication link.

[0062] Example 11 is the test and measurement instrument of Example 10, wherein each of the high-bandwidth communication link and the low-latency communication link includes a switch, and the switch is configured to couple the second test and measurement instrument and the one or more additional test and measurement instruments to the first test and measurement instrument.

[0063] Example 12 is the test and measurement instrument of Example 11, where the high-bandwidth communication link is a Peripheral Component Interconnect Express (PCIe) communication link, and the switch in the high-bandwidth communication link is a PCIe switch.

[0064] Example 13 is the test and measurement instrument of Example 12, where the low-latency communication link further includes one of the following: a Field Programmable Gate Array (FPGA) and an Application Specific Integrated Circuit (ASIC), and the Field Programmable Gate Array (FPGA) and the Application Specific Integrated Circuit (ASIC) implement the switch of the low-latency communication link.

[0065] Example 14 is the test and measurement instrument of Example 1, where at least one of the first test and measurement instrument and the second test and measurement instrument is an oscilloscope.

[0066] Example 15 is a method, including: determining in a first test and measurement instrument whether communication with a second test and measurement is necessary; determining in the first test and measurement instrument the type of the necessary communication; in the first test and measurement instrument, based on the type of the communication, selecting one of the following: a high-bandwidth communication link, the high-bandwidth communication link having a first latency and being coupled between the first test and measurement instrument and the second test and measurement instrument; and a low-latency communication link, the low-latency communication link also being coupled between the first test and measurement instrument and the second test and measurement instrument, the low-latency communication link being independent of the high-bandwidth communication link and having a second latency less than the first latency for communication with the second test and measurement instrument; and communicating with the second test and measurement instrument via the selected high-bandwidth communication link or low-latency communication link.

[0067] Example 16 is the method of Example 15, where the type of the communication is one of the following: transfer of test data between the first test and measurement instrument and the second test and measurement instrument; and control commands to be passed between the first test and measurement instrument and the second test and measurement instrument.

[0068] Example 17 is the method of Example 16, where making the selection further includes: when the type of the communication is transfer of test data between the first test and measurement instrument and the second test and measurement instrument, selecting the high-bandwidth communication link; and when the type of the communication is control commands to be passed between the first test and measurement instrument and the second test and measurement instrument, selecting the low-latency communication link.

[0069] Example 18 is a test and measurement system, comprising: a first test and measurement instrument; a plurality of additional test and measurement instruments; and a dual-band communication link coupled between the first test and measurement instrument and the plurality of additional test and measurement instruments, the dual-band communication link being configured to provide a high-bandwidth communication link with a first latency for transmitting test data between the first test and measurement instrument and each of the plurality of additional test and measurement instruments, and the dual-band communication link being further configured to provide a low-latency communication link independent of the high-bandwidth communication link, the low-latency communication link having a second latency less than the first latency for transferring control commands between the first test and measurement instrument and each of the plurality of additional test and measurement instruments.

[0070] Example 19 is the test and measurement system of Example 18, wherein each of the high-bandwidth communication link and the low-latency communication link includes an intermediate switch coupled between the first test and measurement instrument and each of the plurality of additional test and measurement instruments.

[0071] Example 20 is the test and measurement system of Example 18, wherein the first test and measurement instrument and each of the plurality of additional test and measurement instruments are oscilloscopes.

[0072] The previously described versions of the disclosed subject matter have many advantages that have been described or will be apparent to those of ordinary skill in the art. Even so, these advantages or features are not required in all versions of the disclosed apparatus, system, or method.

[0073] Additionally, the written description refers to specific features. It is understood that the disclosure in this specification includes all possible combinations of these specific features. In the case where a specific feature is disclosed in the context of a particular aspect or example, the feature can also be used, to the extent possible, in the context of other aspects and examples.

[0074] Furthermore, when a method having two or more defined steps or operations is recited in this application, the defined steps or operations can be performed in any order or simultaneously, unless the context excludes these possibilities.

[0075] While specific examples of the invention have been illustrated and described for purposes of illustration, it will be understood that various modifications can be made without departing from the spirit and scope of the invention. Accordingly, the invention should not be limited except as by the appended claims.

Claims

1. A test and measurement system, comprising: First Test and Measurement Instruments; Second test and measurement instrument; and A dual-band communication link is coupled between a first test and measurement instrument and a second test and measurement instrument, the dual-band communication link including a high-bandwidth communication link having a first delay to transmit test data between the first test and measurement instrument and the second test and measurement instrument, and including a low-latency communication link independent of the high-bandwidth communication link, the low-latency communication link having a second delay less than the first delay to transmit control commands between the first test and measurement instrument and the second test and measurement instrument.

2. The test and measurement system of claim 1, further comprising: a first instrument controller, in the first test and measurement instrument, the first instrument controller configured to identify one of the high-bandwidth communication link and the low-latency communication link for communication with the second test and measurement instrument, and further configured to initiate communication via the identified one of the high-bandwidth communication link and the low-latency communication link; as well as A second instrument controller, in the second test and measurement instrument, the second instrument controller is configured to identify one of the high-bandwidth communication link and the low-latency communication link for communication with the first test and measurement instrument, and is further configured to initiate communication via the identified one of the high-bandwidth communication link and the low-latency communication link.

3. The test and measurement system of claim 2, wherein the first instrument controller is configured to: identify a high-bandwidth communication link for communication with the second test and measurement instrument when test data collected by the second test and measurement instrument is to be transmitted to the first test and measurement instrument; and wherein the second instrument controller is configured to: identify a high-bandwidth communication link for communication with the first test and measurement instrument when test data collected by the first test and measurement instrument is to be transmitted to the second test and measurement instrument.

4. The test and measurement system of claim 2, wherein the first instrument controller is configured to: identify a low latency communication link for communicating with the second test and measurement instrument when the first instrument controller determines that the control command is to be passed to the second test and measurement instrument.

5. The test and measurement system of claim 2, wherein the high bandwidth communication link is one of: a peripheral component interconnect express (PCIe) communication link, a universal serial bus (USB) communication link, and an Ethernet communication link.

6. The test and measurement system of claim 5 , wherein the first instrument controller includes a direct memory access (DMA) core, and the high-bandwidth communication link includes a PCIe core, the DMA core and the PCIe core being configured to operate in combination to transfer test data acquired by the second test and measurement instrument via the PCIe communication link, and to store the test data in the first test and measurement instrument.

7. The test and measurement system of claim 2, wherein the low latency communication link comprises one of: a serial communication link comprising a universal asynchronous receiver-transmitter (UART) or a serial communication link comprising a serial peripheral interface (SPI).

8. The test and measurement system of claim 2, wherein the first instrument controller comprises a low-latency protocol kernel, and the low-latency communication link comprises a low-latency communication kernel, the low-latency protocol kernel and the low-latency communication kernel being configured to operate in combination to transmit control commands to the second test and measurement instrument via the low-latency communication link.

9. The test and measurement system of claim 8, wherein the low-latency communication link comprises one of: a field programmable gate array (FPGA) and an application specific integrated circuit (ASIC), the field programmable gate array (FPGA) and the application specific integrated circuit (ASIC) being configured to implement a low-latency communication core.

10. The test and measurement system of claim 1, further comprising one or more additional test and measurement instruments coupled to the first test and measurement instrument via a dual-band communication link.

11. The test and measurement system of claim 10, wherein each of the high bandwidth communication link and the low latency communication link comprises a switch configured to couple the second test and measurement instrument and the one or more additional test and measurement instruments to the first test and measurement instrument.

12. The test and measurement system of claim 11, wherein the high-bandwidth communication link is a Peripheral Component Interconnect Express (PCIe) communication link, and the switch in the high-bandwidth communication link is a PCIe switch.

13. The test and measurement system of claim 12, wherein the low-latency communication link further comprises one of: a field programmable gate array (FPGA) and an application-specific integrated circuit (ASIC), the field programmable gate array (FPGA) and the application-specific integrated circuit (ASIC) implementing a switch of the low-latency communication link.

14. The test and measurement system of claim 1, wherein at least one of the first test and measurement instrument and the second test and measurement instrument is an oscilloscope.

15. A method comprising: determining in the first test and measurement instrument whether communication with the second test and measurement is necessary; determining the type of necessary communications in the first test and measurement instrument; In the first test and measurement instrument, based on the type of communication, one of the following is selected: a high-bandwidth communication link, the high-bandwidth communication link having a first delay, coupled between the first test and measurement instrument and the second test and measurement instrument; and a low-latency communication link, the low-latency communication link also coupled between the first test and measurement instrument and the second test and measurement instrument, the low-latency communication link being independent of the high-bandwidth communication link and having a second delay less than the first delay, for communication with the second test and measurement instrument; as well as Communicate with the second test and measurement instrument via the selected high bandwidth communication link or low latency communication link.

16. The method of claim 15, wherein the type of communication is one of: transmission of test data between the first test and measurement instrument and the second test and measurement instrument; and control commands to be passed between the first test and measurement instrument and the second test and measurement instrument.

17. The method of claim 16, wherein selecting further comprises: When the type of communication is the transfer of test data between the first test and measurement instrument and the second test and measurement instrument, selecting the high bandwidth communication link; as well as When the type of communication is that control commands are to be communicated between the first test and measurement instrument and the second test and measurement instrument, a low latency communication link is selected.

18. A test and measurement system comprising: First Test and Measurement Instruments; multiple additional test and measurement instruments; and A dual-band communication link is coupled between the first test and measurement instrument and the plurality of additional test and measurement instruments, the dual-band communication link being configured to provide a high-bandwidth communication link having a first delay to transmit test data between the first test and measurement instrument and each of the plurality of additional test and measurement instruments, and the dual-band communication link being further configured to provide a low-latency communication link independent of the high-bandwidth communication link, the low-latency communication link having a second delay less than the first delay to transmit control commands between the first test and measurement instrument and each of the plurality of additional test and measurement instruments.

19. The test and measurement system of claim 18, wherein each of the high bandwidth communication link and the low latency communication link comprises an intermediate switch coupled between the first test and measurement instrument and each of the plurality of additional test and measurement instruments.

20. The test and measurement system of claim 18, wherein the first test and measurement instrument and each of the plurality of additional test and measurement instruments is an oscilloscope.

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