Automatic test equipment and method for generating waveforms - Patents.com

Abstract

An example of automatic test equipment (ATE) includes a first test instrument for receiving a waveform from a device under test, the waveform being based on a test signal transmitted from the ATE to the DUT, circuitry for generating digital pulses based on the waveform, and a second test instrument for receiving the digital pulses on at least two digital pins and processing the digital pulses to test the DUT.

Description

[Technical field]

[0001] This specification describes example implementations of a test system configured to generate a waveform based on a digital pulse, and configured to test a device based on the waveform. [Background technology]

[0002] Test systems are configured to test the operation of electronic devices, such as microprocessors and memory chips. Testing may involve sending signals to the devices and determining how well the devices reacted to those signals based on the device's response. The device's response indicates whether the device passed or failed the test. Summary of the Invention [Means for solving the problem]

[0003] An example of an ATE includes a first test instrument including digital pins, the first test instrument configured to output pulses on at least two of the digital pins, circuitry for combining the pulses to generate a signal and generating a waveform based on the signal, and a second test instrument for performing one or more tests on a device under test (DUT) based on the waveform. The example ATE may include one or more of the following features, alone or in combination:

[0004] The first test instrument may include a pattern generator for controlling the pulse. The first test instrument may include a digital instrument that is programmable to generate a pulse and change parameters of the pulse on the at least two digital pins. The first test instrument may include a digital instrument that is programmable to control the timing of the pulse on the at least two digital pins. The first test instrument may include a digital instrument that is programmable to control the width of the pulse on the at least two digital pins. The first test instrument may include a digital instrument that is programmable to control the polarity of the pulse on the at least two digital pins. The first test instrument may include a digital instrument that is programmable to control the position of the pulse on the at least two digital pins. The first test instrument may include a digital instrument that is programmable to control the delay of the pulse on the at least two digital pins.

[0005] The ATE may include circuitry for modulating a radio frequency (RF) carrier signal with the waveform to generate a test signal. The second test equipment may be configured to perform one or more tests by outputting the test signal to the DUT. The second test equipment may be configured to perform one or more tests by outputting the waveform to the DUT. The first test equipment may be digital test equipment and the second test equipment may be radio frequency (RF) test equipment. The circuitry may include a band pass filter.

[0006] The at least two digital pins may include two or more pairs of digital pins. The two or more pairs of digital pins may include a first pair of digital pins and a second pair of digital pins. A first pulse on the first pair of digital pins may be wider than a second pulse on the second pair of digital pins. The circuitry may include a summer for summing the first pulse and the second pulse.

[0007] The at least two digital pins may include two or more pairs of digital pins. The two or more pairs of digital pins may include a first pair of digital pins and a second pair of digital pins. A first pulse on the first pair of digital pins may have a different amplitude than a second pulse on the second pair of digital pins. The circuitry may include a summer for summing the first pulse and the second pulse.

[0008] The signal may be an intermediate signal, and generating the waveform may include filtering the intermediate signal to generate the waveform. Adding the first pulse and the second pulse may generate an intermediate signal having multiple stages.

[0009] The waveform may be divided into time slots. Each time slot may encode multiple bits of data based on the polarity of the waveform within the time slot and the timing of a minimum or maximum within the time slot. The waveform may encode two bits per time slot. The first of the two bits may be based on the polarity, and the second of the two bits may be based on whether the minimum or maximum is closer to the beginning or end of the time slot.

[0010] The first test instrument may be configured to introduce delays to pulses on at least two digital pins to simulate a time-of-flight delay of a waveform through air. The waveforms may be generated independently of a dedicated waveform generator. At least one of the digital pins may be controllable to drive three levels, the three levels including logic high, logic low, and high impedance.

[0011] An example of an ATE includes a first test instrument for receiving a waveform from the DUT, the waveform being based on a test signal transmitted from the ATE to the DUT, circuitry for generating digital pulses based on the waveform, and a second test instrument for receiving the digital pulses on at least two digital pins and processing the digital pulses to test the DUT. An example of an ATE may include one or more of the following features, either alone or in combination.

[0012] The first test equipment may be a radio frequency (RF) test equipment. The second test equipment may be a digital test equipment. The waveform may include a number of time slots. Each time slot may include a portion of the signal consisting of a minimum or a maximum. Generating the digital pulses may include identifying the minimum or maximum and splitting the minimum or maximum into one or more digital pulses for output on at least two digital pins.

[0013] An example method includes generating a waveform. The example method includes outputting pulses on at least two digital pins of the ATE, combining the pulses to generate a signal, generating a waveform based on the signal, and performing one or more tests on a DUT being tested by the ATE based on the waveform. The example method may include one or more of the following features, alone or in combination.

[0014] An example method may include controlling a pulse with a pattern generator. An example method may include programming a digital device to generate a pulse on at least two digital pins. An example method may include programming a digital device to control a timing of a pulse on at least two digital pins. An example method may include programming a digital device to control a polarity of a pulse on at least two digital pins. An example method may include programming a digital device to control a position of a pulse on at least two digital pins. An example method may include programming a digital device to control a delay of a pulse on at least two digital pins.

[0015] An example method may include modulating a radio frequency (RF) carrier signal with the waveform to generate a test signal. Performing the one or more tests may include outputting the test signal to a DUT. An example method may include performing the one or more tests with the waveform.

[0016] The ATE may include digital test equipment including at least two digital pins, radio frequency (RF) test equipment for performing one or more tests on the DUT, and circuitry for modulating a radio frequency (RF) carrier signal with a waveform to generate a test signal for output by the RF test equipment to the DUT for performing one or more tests. The waveform may be filtered with a band pass filter. The at least two digital pins may include two or more pairs of digital pins. The two or more pairs of digital pins may include a first pair of digital pins and a second pair of digital pins. A first pulse on the first pair of digital pins may be wider than a second pulse on the second pair of digital pins. Combining the pulses may include summing the first pulse and the second pulse. Generating the waveform may include filtering the signal. An example method may include summing the first pulse and the second pulse to generate a signal having multiple stages.

[0017] The waveform may be divided into time slots, with each time slot encoding multiple bits of data based on the polarity of the waveform within the time slot and the timing of a minimum or maximum within the time slot. The waveform may encode two bits per time slot. The first of the two bits may be based on the polarity, and the second of the two bits may be based on whether the minimum or maximum is closer to the beginning or end of the time slot.

[0018] An example method can include introducing a delay into a pulse on at least two digital pins to simulate a time-of-flight delay of a waveform through air.An example method can include programming a digital device to control a width of the pulse on the at least two digital pins.

[0019] Any two or more of the features described in this specification, including this summary, may be combined to form implementations not described in detail herein.

[0020] At least some of the example test systems and processes described herein may be configured or controlled by one or more processing devices executing instructions stored on one or more non-transitory machine-readable storage media. Examples of non-transitory machine-readable storage media include read-only memory, optical disk drives, memory disk drives, and random access memories. At least some of the example test systems and processes described herein may be configured or controlled using a computing system comprised of one or more processing devices and a memory that stores instructions executable by the one or more processing devices to perform various control operations.

[0021] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a block diagram of an example test system. [Diagram 2] FIG. 2 is a block diagram of an example of a circuit configuration included in the test system. [Diagram 3] 4 is a graph of an example of a waveform that can be generated by a test system based on a digital pulse. [Figure 4] 1 includes a graph showing the digital pulses used to generate the waveform. [Diagram 5] 4 is an example of an intermediate signal generated based on a digital pulse. [Figure 6] Contains a graph of the digital pulses output on two pairs of digital pins of a digital test instrument. [Figure 7] 1 is a graph of an intermediate signal generated by combining pulses from two pairs of digital pins of a digital test instrument. [Figure 8] 1 shows a portion of an intermediate signal generated by combining pulses from three digital pins of a digital test instrument. [Figure 9]1 shows a portion of an intermediate signal generated by combining pulses from four digital pins of a digital test instrument. [Figure 10] 4 is a flow chart illustrating an example process for generating test signals based on pulses output on digital pins of digital test equipment. [Figure 11] 11 is a flowchart illustrating an example of a process for generating a digital pulse from a response signal received from a device under test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The same reference numbers in different drawings indicate the same elements.

[0024] Automatic test equipment (ATE) is an example of a test system used to test electronic devices. The ATE may be modular in that it includes multiple test instruments that may be connected to and separated from the ATE. In an example, the test instruments are electronic devices configured to send signals to a device under test (DUT) and determine how the DUT reacted to those signals based on the response of the DUT. Examples of test instruments that may be part of the ATE include digital test instruments and radio frequency (RF) test instruments. Digital test instruments include digital pins that output and receive digital data, also called pulses. RF test instruments may include coaxial cables or other transmission media that output and receive radio frequency signals. Additionally, other types of test instruments that output and receive other types of signals may be included in the ATE.

[0025] In an example, the ATE includes a first test instrument having digital pins. The first test instrument may include a digital instrument configured to output pulses on at least two of the digital pins. For example, the first test instrument may be configured to output a first train of pulses on the first digital pin and a second, different train of pulses on the second digital pin. A pattern generator in the first test instrument may be configured to control the pulses on the pins. Circuitry, such as a digital summer, may be configured to combine pulses from the first digital pin and the second digital pin to generate an intermediate signal. The intermediate signal may be a digital signal including pulses having positive and negative polarities. A filter, such as a band pass filter (BPF), may be configured to filter the intermediate signal to generate an analog waveform. A second test instrument, such as an RF test instrument, may perform one or more tests of the DUT based on the waveform. Thus, the ATE may use digital pins on one test instrument, such as a digital test instrument, to generate a signal used for testing by another test instrument, such as an RF test instrument. This can be done independently of, for example without, any dedicated waveform generator (AWG) equipment. This is particularly advantageous when dealing with waveforms having a bandwidth of about 500 megahertz (MHz) or more. In this regard, signals having a bandwidth of about 500 MHz or more can be expensive to generate using an AWG and difficult to measure using standard ATE baseband equipment. In some implementations, standard digital equipment can be used, or an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA) can be used to generate one or more trains of pulses on a digital pin.

[0026] Figure 1 shows an example of an ATE 10 that is modular and configurable to generate waveforms for testing based on pulse outputs on digital pins. In Figure 1, the dashed lines indicate possible signal paths between devices and equipment in the ATE and do not necessarily represent actual transmission media.

[0027] ATE 10 includes a test head 11 and a test computer 12. Test head 11 interfaces with a DUT (not shown) on which testing is performed. Test computer 12 communicates with test head 11 to control the testing. For example, test computer 12 may download a set of test programs to test instruments on the test head, and then execute the set of test programs and communicate with the test head to test the DUT.

[0028] The ATE 10 includes test equipment 13A-13N. In this example, one or more of the test equipment includes one or more digital test equipment configured to output digital test signals to test the DUT and one or more RF test equipment configured to output RF signals to test the DUT. However, in addition to digital test equipment and RF test equipment, other types of test equipment may be used. For example, test equipment configured to push analog voltages and currents into test channels to test the DUT may be used. Each test equipment may be configured to output test signals to test the DUT and to receive signals from the DUT. The received signals may include response signals based on the test signals and / or signals originating from the DUT that are not prompted by, e.g., not responsive to, the test signals.

[0029] Signals are transmitted to and received from the DUT across multiple test channels. In some examples, the test channels may include a physical transmission medium or multiple physical transmission media over which signals are transmitted from the test equipment to the DUT and signals are received from the DUT. The physical transmission media may include, but are not limited to, electrical conductors alone or optical conductors, in combination with wireless transmission media, or both optical conductors and wireless transmission media. The electrical conductors may include coaxial cables transmitting RF signals. In some examples, the test channels may include various frequencies transmitting signals across one or more physical transmission media.

[0030] The ATE 10 includes a connection interface 14 that connects the test equipment test channels 15 to the DIB 16. The connection interface 14 may include connectors 20 or other devices that route signals between the test equipment and the DIB 16. For example, the connection interface may include one or more circuit boards or other substrates that mount such connectors. Conductors that define the equipment test channels may be routed through the connection interface and the DIB.

[0031] 1, DIB 16 electrically and mechanically connects to test head 11. The DIB includes sites 21 that may include pins, conductors, or electrical and mechanical connection points to which the DUTs connect. Test signals, response signals, and other signals pass through test channels across the sites between the DUTs and test equipment. In addition, DIB 16 includes, among other things, connectors, conductors, and test equipment, circuitry for routing signals between the DUTs connected to sites 21, and other circuitry.

[0032] In the example of FIG. 1, test equipment 13A is a digital test equipment referred to as digital equipment 13A. In the example of FIG. 1, test equipment 13B is an RF test equipment referred to as RF equipment 13B. Digital equipment 13A includes a number of digital pins that output test signals to and receive test signals from the DUT. Each digital pin may be a separate channel between the digital equipment and the DIB. RF equipment 13B includes one or more coaxial connections that output test signals to and receive test signals from the DUT. Each coaxial connection may be a separate channel between the digital equipment and the DIB. In an example, a coaxial connection includes a transmission line having a conductive outer material surrounding an insulating material, which in turn surrounds a center conductor. The outer material serves as a return for the center conductor. In some implementations, a transmission medium other than a coaxial connection may be used to implement the test channel between the RF equipment and the DIB.

[0033] Additionally, the ATE 10 includes circuitry to convert the pulses output on the digital pins into waveforms that are modulated with an RF carrier signal to generate a test signal. The test signal may be, for example, an output from an RF device to a DUT. The circuitry may be configured to convert the waveforms into digital pulses for use in a digital device. In some implementations, this circuitry (CKT) 22 may be located in the DIB 16, as shown by the dashed lines in FIG. 1. In these implementations, communication between the digital device 13A and the RF device 13B passes through the DIB 16. In some implementations, this circuitry 22 may be located in the RF device 13B, as shown by the dashed lines in FIG. 1. In these implementations, communication between the digital device 13A and the RF device 13B is direct, as conceptually illustrated by arrow 23, and does not pass through the DIB.

[0034] FIG. 2 shows an example of an implementation of components of circuitry 22 that generates a test signal. Circuitry 22 includes a digital summer circuit 24 that receives pulses at inputs 25, 25 and combines the pulses to generate intermediate signal 27, which is a digital signal. For example, the pulses may be summed to generate the intermediate signal. Circuitry 22 includes a filter 29, in this example a bandpass filter, that generates a waveform based on the intermediate signal. Typically, the filter smoothes the intermediate signal, which is digital, to generate a waveform, which is analog. In some implementations, the intermediate signal and the waveform may be the same signal. That is, the intermediate signal may be the waveform that is used and the waveform may be generated only by passing the intermediate signal.

[0035] The modulator circuit 31 modulates an RF carrier signal with a waveform to generate a test signal, e.g., an analog RF test signal. In an example, the RF test equipment outputs a test signal to the DUT and receives a response signal from the DUT. The response signal may also be an RF signal. In some implementations, the circuitry 22 further includes a demodulator circuit 33 that demodulates the response signal to generate a waveform and an analog-to-digital converter (ADC) 34 that generates a digital signal based on the waveform. The digital signal may then be sent to the digital equipment 13A for processing. In some implementations, the response signal may be processed by the RF equipment 13B. Processing in either case may include determining whether the DUT has passed or failed the test given the known stimulus and response.

[0036] FIG. 3 shows an example of a waveform 35 that can be modeled and generated using the system described herein. The waveform 35 can encode data using biorthogonal keying. The waveform 35 can be divided into time slots, such as time slots 36 and 40. Each time slot can include a maximum 37, as in time slot 36, or a minimum, such as minimum 39, in time slot 40. The waveform 35 can be generated from pulses that make up digital data. FIG. 4 shows an example of a set of pulses 48 that can be used to generate the waveform 35. Pulses for a portion 41 of the waveform with positive polarity can be output from a digital device to a test channel on a first digital pin. This series of pulses is represented by channel 50. Pulses for a portion 42 of the waveform with negative polarity can be output from a digital device to a test channel on a second digital pin that is different from the first digital pin. This series of pulses is represented by channel 51. In some implementations, the polarity indicates whether the signal is positive or negative.

[0037] To generate the intermediate signal shown in Figure 5, a first pulse for a portion 41 of the waveform having a positive polarity is added at input 25 of summer circuit 24, and a second pulse for a portion 42 of the waveform representing a negative polarity is subtracted at summer input 26. In the example of Figure 5, the resulting intermediate signal 43 includes a portion 44 having a positive polarity and a portion 45 having a negative polarity. The example of Figure 5 is shown as a square wave, but this need not be the case. Filter 29 and modulator circuit 31 generate a test signal based on intermediate signal 43 in the manner described above.

[0038] In some implementations, the test equipment is programmable to control the timing of a pulse on a digital pin, control the width of a pulse on a digital pin, control the polarity (positive or negative) of a pulse on a digital pin, control the position of a series or sequence of pulses, and control, e.g., introduce, a delay of a pulse on a digital pin. For example, the test equipment can be configured to delay a pulse on a digital pin to simulate a time-of-flight delay of a waveform through air. This is useful to simulate localization functionality for a device being tested. In an example, localization involves outputting a signal and detecting reflections of that signal. This is done multiple times and at multiple different locations. By correlating the reflections with the output, the device can determine the distance the signal has traveled. By knowing the distance the signal has traveled relative to multiple, e.g., three, reference locations, the device can determine the location of the device relative to the reference locations. In some implementations, timing, delay, and location are related. For example, timing can refer to the location of a pulse relative to a location in a pattern or the pattern timing of another waveform.

[0039] As described, the test instrument is programmable to control the timing of the pulses on one or more of the digital pins and to control the width of the pulses on the digital pins. By controlling the pulse width and the timing of the pulses on the digital pins, an intermediate signal having multiple stages can be generated. Increasing the number of stages can improve the resolution of the final waveform. For example, with reference to FIG. 6, a first pair 55 of digital pins on the digital instrument can output a pulse having a first narrow width. A second pair 56 of digital pins on the digital instrument can output a pulse having a second wider width. In this context, the terms narrow and wide do not have any particular numerical connotation, but rather refer to relative widths. The centers of the narrow and wide pulses on each pin are aligned. In the above-described manner, pulses for portions of the waveform from different digital pins having positive polarity are added, and pulses for portions of the waveform from different digital pins having negative polarity are subtracted. For the pulses of FIG. 6, the resulting intermediate signal 58 of FIG. 7 includes a stepped portion 59 having positive polarity and a stepped portion 60 having negative polarity. These stepped portions are formed for the addition or subtraction of different pulses having different widths. In an example, pulses 61 and 62 in Figure 6 are combined, resulting in a summation of a portion 63 of intermediate signal 58 having a magnitude equal to the magnitude of pulse 62 and a portion 64 having a magnitude equal to the magnitudes of pulses 61 and 62. For example, if pulse 61 has a magnitude of 1 and pulse 62 has a magnitude of 1, then portion 63 has a magnitude of 1 and portion 64 has a magnitude of 2, i.e. 1+1.

[0040] By increasing the number of pulses combined and the number of different widths of the pulses, the shape and / or resolution of the intermediate signal can be changed. For example, FIG. 8 shows a portion of an example intermediate signal generated using three pairs of digital pins, each pair having a different pulse width. For example, FIG. 9 shows a portion of an example intermediate signal generated using four pairs of digital pins, each pair having a different pulse width. As described above, the filter smoothes the intermediate waveform, and the modulator circuit modulates the RF carrier signal with the waveform to generate a test signal. The test signal can then be used as described herein to test, for example, a DUT.

[0041] In some implementations, the pulses may be time-shifted relative to one another and may have the same width and / or different amplitudes. Pulses with these characteristics may be used to synthesize quantized analog waveforms, i.e., intermediate signals.

[0042] The 802.15.4g standard can operate in different frequency bands. The lowest frequency band can be accessed directly with digital pulses without modulating the RF carrier. Thus, in some implementations, the test signal can be a waveform (baseband signal) or a waveform can be modulated onto the RF carrier as described.

[0043] As discussed above, a waveform, such as waveform 35 of FIG. 3, may encode data using biorthogonal keying. As discussed above, waveform 35 may be divided into time slots, such as time slots 36 and 40. Each time slot may include a maximum 37, as in the case of time slot 36, or a minimum 39, as in the case of time slot 40. Each time slot encodes multiple bits of data based on the polarity of the waveform within the time slot and the timing of the minimum or maximum within the time slot. For example, waveform 35 may encode two bits per time slot. The first of the two bits may be based on the polarity of the signal within that time slot, and the second of the two bits may be based on whether the minimum or maximum is closer to the beginning or end of the time slot. In an example, a single time slot may transmit two bits having the following values: 00, 01, 10, 11. In this example, 00 is indicated by positive polarity and a maximum before the midpoint of the timeslot, 01 is indicated by positive polarity and a maximum after the midpoint of the timeslot, 10 is indicated by negative polarity and a minimum before the midpoint of the timeslot, and 11 is indicated by negative polarity and a minimum after the midpoint of the timeslot.

[0044] In some implementations, a waveform, such as waveform 35, may encode different data than described above. For example, each time slot may encode three bits. A first of the three bits may be based on polarity, a second of the three bits may be based on whether the minimum or maximum is within the first or second half of the time slot, and a third of the three bits may be based on whether the minimum or maximum is closer to the midpoint of the time slot or closer to the beginning or end of the time slot. Other encodings that generate more than three bits per time slot may be used.

[0045] FIG. 10 illustrates an example process 70 that may be performed by an ATE to generate test signals using an example system described herein. Process 70 includes generating (71) pulses to be used to generate waveforms for testing. Generating the pulses may include digital equipment outputting a series of ones and zeros, e.g., high and low logic or voltage levels, on one or more pairs of digital pins. For example, a pattern generator controlling a first digital pin may output logic levels representing a portion of a waveform having positive polarity. For example, a pattern generator controlling a second digital pin may output logic levels representing a portion of a waveform having negative polarity. The pulses are output at two or more of the digital pins across a corresponding transmission medium to circuitry 22 that generates waveforms and test signals based on the pulses. As described, in some examples the circuitry is located in the DIB and in some examples the circuitry is located in another piece of test equipment, e.g., RF equipment.

[0046] The circuitry combines (72) the pulses to generate an intermediate signal. As described, the pulses may be summed to generate the intermediate signal. Summing may include combining pulses from two, four, six, eight, ten, etc. digital pins to generate the intermediate signal. Generally, the more digital pins used, the more resolution the intermediate signal will have. In some implementations, an even number of digital pins are used, with one digital pin of each pair of digital pins representing the positive polarity portion of the signal and the other digital pin of each pair of digital pins representing the negative polarity portion of the signal. In some implementations, this need not be the case. For example, if the waveform is to have a single polarity, it is not necessary to subtract pulses to generate two polarities. In such cases, one, two, three, four, five, six, etc. digital pins may have pulses that are to be combined to generate an intermediate signal of the appropriate resolution.

[0047] The circuitry filters (73) the intermediate signal to generate a waveform. As mentioned above, in some implementations, the filter used is a band pass filter (BPF). The band pass filter may smooth the intermediate signal to generate a waveform. In some implementations, the band pass filter is configured to generate a specific type of waveform. For example, the waveform in FIG. 3 is a square root cosine time domain pulse that can be generated using two digital pins, one for positive polarity and one for negative polarity, and the intermediate signal generated using an appropriately configured band pass filter. In some implementations, filters other than band pass filters may be used to generate a waveform from the intermediate signal.

[0048] The modulator circuitry modulates (74) the RF carrier signal with the waveform to generate a test signal. If desired, the test signal may be transmitted from circuitry external to the RF equipment to the equipment, e.g., the RF equipment. The RF equipment uses the test signal to perform (75) one or more tests of the DUT being tested by the ATE.

[0049] 11 illustrates an example process 80 that may be performed by the ATE to generate a digital pulse based on an analog, e.g., RF, response signal received by the ATE from the DUT. According to process 80, the response signal is received (81) by circuitry 22. The response signal is demodulated (82) to generate an intermediate signal. The intermediate signal is then digitized (83) to generate a digital pulse representative of the intermediate signal. The digital pulse is output over one or more communication channels to a digital pin on a digital device. The digital signal may then be analyzed to determine the response of the DUT to the stimulus signal that generated the response signal. The response of the DUT indicates whether the DUT passed or failed the test.

[0050] In some implementations, at least one of the digital pins is controllable to drive three levels, including logic high, logic low, and high impedance. In some implementations, at least two of the digital pins, for example the digital pins corresponding to inputs 25 and 25, are controllable to drive three levels, including logic high, logic low, and high impedance. In some implementations, all of the digital pins in the test equipment or test system are controllable to drive three levels, including logic high, logic low, and high impedance.

[0051] In some implementations, the example test systems described herein are synchronous, and the timing / delay references described herein are referenced to a reference timing clock used throughout the test system.

[0052] All or part of the testing system and processes described herein and in various modifications may be configured or controlled at least in part by one or more computers using one or more computer programs tangibly embodied in one or more information media, such as one or more non-transitory machine-readable storage media. The computer programs may be written in any type of programming language, including compiled or interpreted languages, and the computer programs may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. The computer programs may be deployed to run on one computer or multiple computers at one site, or may be distributed across multiple sites and interconnected by a network.

[0053] Operations relating to the configuration or control of the test system and processing may be performed by one or more programmable processors executing one or more computer programs to control all or a portion of the applicable operations described above. All or a portion of the test system and processing may be configured or controlled by special purpose logic circuitry, such as an FPGA (field programmable gate array) and / or an ASIC (application specific integrated circuit).

[0054] Processors suitable for the execution of a computer program include, by way of example, general purpose and special purpose microprocessors, and any one or more processors of any kind of digital computer. Typically, a processor receives instructions and data from a read-only or random access memory area, or both. Elements of a computer include one or more processors for executing instructions and one or more storage devices for storing instructions and data. Typically, a computer further includes one or more machine-readable storage media, such as a mass storage device for storing data, such as a magnetic disk, a magneto-optical disk, or an optical disk, or is operatively coupled to receive data from, transfer data to, or receive and transfer data to, a machine-readable storage medium. Suitable non-transitory machine-readable storage media for embodying computer program instructions and data include all forms of non-volatile storage including, by way of example only, semiconductor storage devices such as EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory) and Flash storage devices, magnetic disks such as internal hard disks or removable disks, magneto-optical disks, and CD-ROMs (Compact Disk-Read-Only Memory) and DVD-ROMs (Digital Versatile Disk-Read-Only Memory).

[0055] Elements of different implementations described may be combined to form other implementations not described in detail above. In general, elements may be omitted from the systems described above without adversely affecting the operation of the elements or the operation of the system. Furthermore, various separate elements may be combined into one or more individual elements to perform the functions described herein.

[0056] Other implementations not specifically described herein are within the scope of the following claims.

Claims

1. 1. An automatic test equipment (ATE), comprising: a first test instrument including a plurality of digital pins, the first test instrument being configured to output pulses on at least two digital pins of the plurality of digital pins, the first digital pin being for a pulse having a positive polarity and the second digital pin being for a pulse having a negative polarity; a circuit configuration including a summer that receives the pulses from the at least two digital pins and combines the pulses to generate a signal, and generates a waveform based on the signal; a second test instrument that performs one or more tests on a device under test (DUT) based on the waveform; and Including, ATE.

2. The ATE of claim 1 , wherein the first test equipment includes a pattern generator that controls the pulses.

3. 2. The ATE of claim 1, wherein the first test instrument comprises digital instrumentation that is programmable to generate the pulses and to change parameters of the pulses on the at least two digital pins.

4. 2. The ATE of claim 1, wherein the first test instrument comprises digital instrumentation programmable to control timing of the pulses on the at least two digital pins.

5. 2. The ATE of claim 1, wherein the first test instrument comprises digital instrumentation programmable to control widths of the pulses on the at least two digital pins.

6. 2. The ATE of claim 1, wherein the first test instrument comprises a digital instrument programmable to control polarity of the pulses on the at least two digital pins.

7. 2. The ATE of claim 1, wherein the first test instrument comprises digital instrumentation programmable to control a position of the pulse on the at least two digital pins.

8. 2. The ATE of claim 1, wherein the first test instrument comprises a digital instrument programmable to control a delay of the pulses on the at least two digital pins.

9. further comprising circuitry for modulating a radio frequency (RF) carrier signal with the waveform to generate a test signal; The ATE of claim 1 , wherein the second test equipment is configured to perform the one or more tests by outputting the test signals to the DUT.

10. The ATE of claim 1 , wherein the second test instrument is configured to perform the one or more tests by outputting the waveforms to the DUT.

11. the first test instrument is a digital test instrument; The ATE of claim 1 , wherein the second test equipment is radio frequency (RF) test equipment.

12. The ATE of claim 1 , wherein the circuitry includes a bandpass filter.

13. the at least two digital pins include two or more pairs of digital pins; the two or more pairs of digital pins include a first pair of digital pins including the first digital pin and a second pair of digital pins including the second digital pin; a first pulse on the first pair of digital pins is wider than a second pulse on the second pair of digital pins; The ATE of claim 1 , wherein the adder is configured to add the first pulse and the second pulse.

14. the at least two digital pins include two or more pairs of digital pins; the two or more pairs of digital pins include a first pair of digital pins including the first digital pin and a second pair of digital pins including the second digital pin; a first pulse on a first pair of digital pins has a different amplitude than a second pulse on the second pair of digital pins; The ATE of claim 1 , wherein the adder is configured to add the first pulse and the second pulse.

15. the signal is an intermediate signal, generating the waveform includes filtering the intermediate signal to generate the waveform; 14. The ATE of claim 13, wherein summing the first pulse and the second pulse produces the intermediate signal having a plurality of stages.

16. The waveform is divided into a number of time slots; 2. The ATE of claim 1, wherein each time slot encodes multiple bits of data based on the polarity of the waveform in that time slot and the timing of minima or maxima in that time slot.

17. the waveform encodes two bits per time slot; a first bit of the two bits based on the polarity; 17. The ATE of claim 16, wherein a second of the two bits is based on whether the minimum or maximum is closer to the beginning or end of the time slot.

18. 2. The ATE of claim 1, wherein the first test instrument is configured to introduce delays into the pulses at the at least two digital pins to simulate localized functionality for the DUT.

19. The ATE of claim 1 , wherein the waveforms are generated without the use of a dedicated waveform generator.

20. At least one of the digital pins is controllable to drive three levels; 2. The ATE of claim 1, wherein the three levels include logic high, logic low, and high impedance.

21. 1. A method for generating a waveform, comprising: Outputting pulses to at least two digital pins of an automatic test equipment (ATE), a first digital pin for pulses having a positive polarity and a second digital pin for pulses having a negative polarity; combining the pulses using a summer to generate a signal; generating the waveform based on the signal; performing one or more tests on a device under test (DUT) being tested by the ATE based on the waveform; The method includes:

22. 22. The method of claim 21, further comprising controlling the pulses with a pattern generator.

23. 23. The method of claim 22, further comprising: programming a digital device to generate the pulses on the at least two digital pins.

24. 24. The method of claim 23, further comprising programming the digital device to control timing of the pulses on the at least two digital pins.

25. 24. The method of claim 23, further comprising programming the digital device to control the polarity of the pulses on the at least two digital pins.

26. 24. The method of claim 23, further comprising programming the digital device to control a position of the pulse on the at least two digital pins.

27. 24. The method of claim 23, further comprising programming the digital device to control a delay of the pulses on the at least two digital pins.

28. modulating a radio frequency (RF) carrier signal with the waveform to generate a test signal; 22. The method of claim 21, wherein performing the one or more tests comprises outputting the test signal to the DUT.

29. 22. The method of claim 21, further comprising performing the one or more tests with the waveform.

30. The ATE comprises: a digital test instrument including the at least two digital pins; a radio frequency (RF) test instrument for performing the one or more tests on the DUT; circuitry for modulating a radio frequency (RF) carrier signal with the waveform to generate a test signal for output to the DUT to perform the one or more tests with the RF test equipment; 22. The method of claim 21 , comprising:

31. 22. The method of claim 21, wherein the waveform is filtered using a bandpass filter.

32. the at least two digital pins include two or more pairs of digital pins; the two or more pairs of digital pins include a first pair of digital pins including the first digital pin and a second pair of digital pins including the second digital pin; a first pulse on the first pair of digital pins is wider than a second pulse on the second pair of digital pins; 22. The method of claim 21, wherein combining the pulses comprises adding the first pulse and the second pulse.

33. generating the waveform includes filtering the signal; 33. The method of claim 32, further comprising summing the first pulse and the second pulse to generate the signal having a plurality of stages.

34. The waveform is divided into a number of time slots; 22. The method of claim 21, wherein each time slot encodes multiple bits of data based on the polarity of the waveform in that time slot and the timing of minima or maxima in that time slot.

35. the waveform encodes two bits per time slot; a first bit of the two bits based on the polarity; 35. The method of claim 34, wherein a second of the two bits is based on whether the minimum or maximum is closer to the beginning or end of the time slot.

36. 22. The method of claim 21, further comprising: introducing a delay into the pulses at the at least two digital pins to simulate localized functionality for the DUT.

37. 22. The method of claim 21, further comprising programming a digital device to control the width of the pulses on the at least two digital pins.

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