Abstract: A test and measurement instrument according to an embodiment of the present invention converts digital data that represents an analog input signal into a time-domain bitmap, and then compares a region of that time-domain bitmap to a density threshold. When the density value violates the density threshold, a trigger signal is generated that causes digital data to be stored into a memory.

Abstract: A signal acquisition system has a signal acquisition probe having probe tip circuitry coupled to a resistive center conductor signal cable. The resistive center conductor signal cable of the signal acquisition probe is coupled to a compensation system in a signal processing instrument via an input node and input circuitry in the signal processing instrument. The signal acquisition probe and the signal processing instrument have mismatched time constants at the input node with the compensation system having an input amplifier with feedback loop circuitry and a shunt pole-zero pair coupled to the input circuitry providing pole-zero pairs for maintaining flatness over the signal acquisition system frequency bandwidth.

Abstract: A test and measurement instrument including an input port configured to receive an input signal; a digitizer configured to digitize the input signal; a decimator coupled to the digitizer and configured to decimate the digitized input signal to generate a decimated input signal; a digital downconverter coupled to the digitizer and configured to frequency shift the digitized input signal to generate a frequency shifted input signal; and a memory configured to store the decimated input signal and the frequency shifted input signal.

Abstract: A test and measurement instrument and method for receiving a radio frequency (RF) signal, digitizing the RF signal using an analog-to-digital converter, downconverting the digitized signal to produce I (in-phase) and Q (quadrature) baseband component information, generating one or more IQ-based time-domain traces using the I and Q baseband component information, and measuring and displaying a variety of measurement values of the IQ-based time-domain traces. The IQ-based time-domain measurement values can be automatically generated and displayed, and/or transmitted to an external device.

Abstract: A signal acquisition system has a signal acquisition probe having probe tip circuitry coupled to a resistive center conductor signal cable. The resistive center conductor signal cable of the signal acquisition probe is coupled to a compensation system in a signal processing instrument via an input node and input circuitry in the signal processing instrument. The signal acquisition probe and the signal processing instrument have mismatched time constants at the input node with the compensation system providing pole-zero pairs for maintaining flatness over the signal acquisition system frequency bandwidth.

Abstract: A test and measurement instrument includes a display having a time domain graticule and a frequency domain graticule. A processor is configured to process an input signal to generate a time domain waveform for display in the time domain graticule, the input signal being correlated to a time base. The processor is also configured to process a second input signal and generate a frequency domain waveform for display in the frequency domain graticule, the second input signal being correlated to the same time base. The frequency domain waveform is correlated to a selected time period of the time base. The processor is also configured to generate a spectrum time indicator configured to graphically illustrate a transform parameter, a location and the selected time period in the time domain graticule with respect to the frequency domain waveform.

Abstract: A mixed signal acquisition system for a test and measurement instrument allows configuring of the number of analog and digital channels in use. The instrument includes an analog input interface and an N-channel logic input interface for receiving an analog signal and an N-channel logic signal, respectively. An A/D converter converts the analog input signal into an N-bit digital signal, and N latch circuits latch the N-bit logic signal. A multiplexer selects either the N-bit digital signal from the A/D converter, or the N-bit logic signals from the N latch circuits, and the selected signal at the output of the multiplexer is stored in an acquisition memory. By controlling the multiplexer selection, the number of analog channels and the digital channels can be controlled.

Abstract: A signal acquisition system has a signal acquisition probe having probe tip circuitry coupled to a resistive center conductor signal cable. The resistive center conductor signal cable is coupled to a compensation system in a signal processing instrument via an input node and input circuitry in the signal processing instrument. The signal acquisition probe and the signal processing instrument have mismatched time constants at the input node with the compensation system having an input amplifier with feedback loop circuitry and a compensation digital filter providing pole-zero pairs for maintaining flatness over the signal acquisition system frequency bandwidth.

Abstract: A test and measurement instrument and method for generating IQ-based time domain waveform information and presenting the IQ-based time domain waveform information together with other time domain waveform on a common axis through a user interface. The test and measurement instrument can include, for example, one or more input terminals to receive an electrical signal under test, an analog-to-digital converter (ADC) to digitize the signal under test, a digital downconverter to produce I (in-phase) and Q (quadrature) baseband component information from the digitized signal, a memory configured to store the IQ baseband component information, a user interface, and a controller. The controller can be configured to generate an IQ-based time domain waveform using the IQ baseband component information, and present the IQ-based time domain waveform and a second time domain waveform on a common axis through the user interface.

Abstract: An improved hold-off algorithm that assures that all data associated with all trigger events in a data signal are displayed uses a designated interval starting with a first trigger event to determine whether any subsequent trigger events occurred within the designated interval. A first display frame is drawn based upon the first trigger event. A next display frame is drawn based either on a next trigger event that occurs outside the designated interval, or based on the last trigger event that occurred within the designated interval. In the latter case the two display frames provide an overlap to assure that no data related to the trigger events is lost on the display.