Abstract: Methods of triggering a test and measurement instrument having a plurality of inputs include the step of generating a trigger signal in response to every occurrence of any one of a plurality of specified trigger events. A first specified trigger event occurs in at least a first one of the inputs and a second specified trigger event occurs in at least a second one of the plurality of inputs. A specified trigger event may include at least one selected input from the plurality of inputs and a selected activity type. Some methods include configuring each of a plurality of event activity detectors to produce a pulse in a logic signal in response to every occurrence of one of the specified trigger events. The plurality of logic signals are combined in a logical OR circuit to generate the trigger signal. Trigger circuits configured according to these methods are also disclosed.

Abstract: A test and measurement instrument includes a coefficient storage facility coupled to a programmable filter. The coefficient storage facility is configured to store at least two pre-determined filter coefficient sets, and configured to pass a selected one of the at least two pre-determined filter coefficient sets to the filter based on a measurement derived using a compensation oscillator. The measurement may include clock delay and clock skew. In some examples the test and measurement instrument may additionally adjust clock delay and/or clock skew in addition to selecting appropriate filter coefficients.

Abstract: A test and measurement instrument, including a splitter configured to split an input signal having a particular bandwidth into a plurality of split signals, each split signal including substantially the entire bandwidth of the input signal, a plurality of harmonic mixers, each harmonic mixer configured to mix an associated split signal of the plurality of split signals with an associated harmonic signal to generate an associated mixed signal, a plurality of digitizers, each digitizer configured to digitize a mixed signal of an associated harmonic mixer of the plurality of harmonic mixers, and a linear time-periodic filter configured to receive the digitized mixed signal from each of the digitizers and output a time-interleaved signal. A first-order harmonic of at least one harmonic signal associated with the harmonic mixers is different from a sample rate of at least one of the digitizers.

Abstract: A ground-penetrating RADAR-based system can include a transmitter configured to transmit multiple RADAR impulses and a receiver configured to receive a signal comprising return waves generated responsive to the transmitted RADAR impulses. The signal can include a direct wave portion and a reflected wave portion. The system can also include a processing unit configured to analyze the return waves by determining the direct wave portion, fitting the direct wave portion to determine parametric information corresponding to the return waves, determining the reflected wave portion, determining characteristics of the reflected wave portion based on the parametric information, and comparing the determined characteristics against known characteristics.

Abstract: A test and measurement instrument includes a coefficient storage facility coupled to a programmable filter. The coefficient storage facility is configured to store at least two pre-determined filter coefficient sets, and configured to pass a selected one of the at least two pre-determined filter coefficient sets to the filter based on a measurement derived using a compensation oscillator. The measurement may include clock delay and clock skew. In some examples the test and measurement instrument may additionally adjust clock delay and/or clock skew in addition to selecting appropriate filter coefficients.

Abstract: An electronically variable analog delay line including at least one segment with an electronically variable inductance. The at least one segment includes a signal path, a ground return path, and a plurality of switches configured to vary the inductance of the segment.

Abstract: An electronically variable analog delay line including at least one segment with an electronically variable inductance. The at least one segment includes a signal path, a ground return path, and a plurality of switches configured to vary the inductance of the segment.

Abstract: A test and measurement instrument, including a splitter configured to split an input signal having a particular bandwidth into a plurality of split signals, each split signal including substantially the entire bandwidth of the input signal, a plurality of harmonic mixers, each harmonic mixer configured to mix an associated split signal of the plurality of split signals with an associated harmonic signal to generate an associated mixed signal, a plurality of digitizers, each digitizer configured to digitize a mixed signal of an associated harmonic mixer of the plurality of harmonic mixers, and a linear time-periodic filter configured to receive the digitized mixed signal from each of the digitizers and output a time-interleaved signal. A first-order harmonic of at least one harmonic signal associated with the harmonic mixers is different from a sample rate of at least one of the digitizers.

Abstract: A test and measurement instrument including a splitter configured to split an input signal having a particular bandwidth into a plurality of split signals, each split signal including substantially the entire bandwidth of the input signal; a plurality of harmonic mixers, each harmonic mixer configured to mix an associated split signal of the plurality of split signals with an associated harmonic signal to generate an associated mixed signal; and a plurality of digitizers, each digitizer configured to digitize a mixed signal of an associated harmonic mixer of the plurality of harmonic mixers. A first-order harmonic of at least one harmonic signal associated with the harmonic mixers is different from an effective sample rate of at least one of the digitizers.

Abstract: A test and measurement instrument includes a coefficient storage facility coupled to a programmable filter. The coefficient storage facility is configured to store at least two pre-determined filter coefficient sets, and configured to pass a selected one of the at least two pre-determined filter coefficient sets to the filter based on a measurement derived using a compensation oscillator. The measurement may include clock delay and clock skew. In some examples the test and measurement instrument may additionally adjust clock delay and/or clock skew in addition to selecting appropriate filter coefficients.

Abstract: A test and measurement instrument including a splitter configured to split an input signal having a particular bandwidth into a plurality of split signals, each split signal including substantially the entire bandwidth of the input signal; a plurality of harmonic mixers, each harmonic mixer configured to mix an associated split signal of the plurality of split signals with an associated harmonic signal to generate an associated mixed signal; and a plurality of digitizers, each digitizer configured to digitize a mixed signal of an associated harmonic mixer of the plurality of harmonic mixers. A first-order harmonic of at least one harmonic signal associated with the harmonic mixers is different from an effective sample rate of at least one of the digitizers.

Abstract: A test system can include a probe suitable to be coupled between a test measurement device and a device under test (DUT). The probe can include a signal input to receive an active signal from the DUT and a signal output to provide the active signal to the test measurement device. The probe can also include an input ground to connect to the DUT ground and an output ground to connect to the test measurement device ground. A probe ground connection checking device can automatically determine whether the probe ground connections to the DUT ground and test measurement device ground are solid.

Abstract: A probe, including a first input configured to receive a first input signal, a second input configured to receive a second input signal, a first cable connected to the first input, a second cable connected to the second input, an electronically adjustable delay connected to the first cable, the electronically adjustable delay configured to delay the first input signal to remove a skew between the first input signal and the second input signal, and an amplifier configured to receive the first input signal from the electronically adjustable delay and a second input signal.

Abstract: A test system can include a probe suitable to be coupled between a test measurement device and a device under test (DUT). The probe can include a signal input to receive an active signal from the DUT and a signal output to provide the active signal to the test measurement device. The probe can also include an input ground to connect to the DUT ground and an output ground to connect to the test measurement device ground. A probe ground connection checking device can automatically determine whether the probe ground connections to the DUT ground and test measurement device ground are solid.

Abstract: A circuit includes a load; a first differential pair coupled to the load and responsive to input data; a second differential pair coupled to the load and responsive to the input data; a third differential pair coupled to the first differential pair and the second differential pair and responsive to a first control signal and a second control signal; a bias circuit configured to pull a node coupled to both the first differential pair and the second differential pair to a predetermined state; and a current source coupled to the third differential pair and the bias circuit.

Abstract: A test and measurement instrument, including an input configured to receive a signal-under-test, a user input configured to accept a first trigger event and a second trigger event from a user, a first trigger decoder configured to trigger on an occurrence of the first trigger event and generate a first trigger signal, a second trigger decoder configured to trigger on an occurrence of the second trigger event occurring after the first trigger event and generate a second trigger signal, and an acquisition system configured to acquire the signal-under-test in response to the first trigger signal and store the acquired signal-under-test based on whether the second trigger signal validates or invalidates the first trigger signal.

Abstract: A ring oscillator timer circuit can include a plurality of electrical components arranged in a cascaded combination of delay stages connected in a closed loop chain. The timer circuit can begin oscillation a programmable number of gate delays after receiving a start signal. In some examples, the number of gate delays can be programmed to fractional values. In further examples, the ring oscillator timer circuit can include a counter having an input electrically coupled to an output of a reset component.

Abstract: A test and measurement system including a device under test, two de-embed probes connected to the device under test, and a test and measurement instrument connected to the two de-embed probes. The test and measurement instrument includes a processor configured to determine the S-parameter set of the device under test based on measurements from the device under test taken by the two de-embed probes.

Abstract: A de-embed probe including an input configured to connect to a device under test, a memory, a signal generator connected to the input, the signal generator configured to generate a test signal, and a controller connected to the signal generator and configured to control the signal generator. The de-embed probe may be used in a test and measurement system. The test and measurement system also includes a test and measurement instrument including a processor connected to the controller of the de-embed probe, the processor configured to provide instructions to the controller, and a test and measurement input to receive an output from the de-embed probe.

Abstract: A test and measurement instrument including a splitter configured to split an input signal having a particular bandwidth into a plurality of split signals, each split signal including substantially the entire bandwidth of the input signal; a plurality of harmonic mixers, each harmonic mixer configured to mix an associated split signal of the plurality of split signals with an associated harmonic signal to generate an associated mixed signal; and a plurality of digitizers, each digitizer configured to digitize a mixed signal of an associated harmonic mixer of the plurality of harmonic mixers. A first-order harmonic of at least one harmonic signal associated with the harmonic mixers is different from an effective sample rate of at least one of the digitizers.