摘要:
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.
摘要翻译:用于测试和测量仪器的混合信号采集系统允许配置正在使用的模拟和数字通道的数量。 仪器包括模拟输入接口和N通道逻辑输入接口,用于分别接收模拟信号和N通道逻辑信号。 A / D转换器将模拟输入信号转换成N位数字信号,N个锁存电路锁存N位逻辑信号。 多路复用器选择来自A / D转换器的N位数字信号或来自N个锁存电路的N位逻辑信号,并且在多路复用器的输出处选择的信号被存储在采集存储器中。 通过控制复用器选择,可以控制模拟通道和数字通道的数量。
摘要:
An apparatus for measuring a parameter of a digitized signal including a digitizer to digitize an input signal into a digitized signal, a rasterizer to generate a raster image from the digitized input signal, a processor to receive the raster image, and a control interface to receive an input control signal indicating a request for a measurement. The rasterizer is responsive to the control signal to generate the raster image from the digitized input signal, and the processor is responsive to the control signal to generate a histogram from the raster image.
摘要:
A low capacitance signal acquisition system has a signal acquisition probe having a low capacitance input circuit coupled to a compensation amplifier in a signal processing instrument via a signal cable. The low capacitance input circuit, the signal cable and the signal processing instrument input have mismatched time constants with the compensation amplifier having feedback loop circuitry providing adjustable gain and pole-zero pairs for maintaining flatness over the low capacitance signal acquisition system frequency bandwidth.
摘要:
A self-adjusting hold-off trigger circuit and method detects a threshold crossing between consecutive samples of a digitized input signal as edge events, identifies the crossing as a qualified trigger event if the crossing is in a desired direction based upon trigger criteria, and provides a trigger output when the qualified trigger event occurs greater than an approximate average or peak time after a preceding edge event.
摘要:
An accessory device voltage management system includes an accessory device selectively coupled to a host. The host provides a bulk power supply and a low power supply voltage to the accessory device. The host receives accessory device parameters from the device and determines if the accessory device is a valid and supported device and, if so, sends commands to the accessory device to couple the bulk power supply voltage to a power supply circuit in the accessory device. The power supply circuit in the accessory device generates at least a first regulated voltage output.
摘要:
A test and measurement instrument includes a memory configured to store a digitized signal, a display configured to display the digitized signal, a mark interface configured to generate a mark creation signal, a processor coupled to the memory, the display, and the mark interface. The processor is configured to identify a feature of the digitized signal and create a mark indicating the feature and the digitized signal in response to the mark creation signal.
摘要:
A noise rejection filter for a trigger circuit uses an algorithm that updates the filter output monotonically so long as the signal slope remains unchanged, maintains the filter output at a constant level when the signal slope changes but the difference between the sample value and the filter output is less than or equal to a hysteresis value, and changes the signal slope while updating the filter output when the difference is greater than the hysteresis value. This maintains the peaks of the input signal at the filter output. The noise rejection filter may be used in a trigger circuit prior to a comparator so that the trigger signal from the comparator accurately reflects the signal pulse width at a desired trigger level and trigger events are detected when the desired trigger level is near the peaks of the input signal.
摘要:
An apparatus for displaying a digitized waveform includes an overview display configured to display a digitized waveform scrolling across the overview display, a zoom display configured to display a portion of the digitized waveform, and a control unit configured to cause the portion of the digitized waveform displayed in the zoom display to track the displayed portion of the digitized waveform in response to a track signal.
摘要:
A multi-instrument triggering system includes in each instrument trigger system a system ready line for coupling an internal ready signal to an external port. A multi-instrument trigger bus cable connects the external ports, trigger event outputs and trigger event inputs of multiple instruments together in such a way as to enable the trigger generators in the instruments when all instruments are ready to receive a trigger event. When enabled, a coordinated trigger is generated in response to an internal trigger event from at one of the instruments. The coordinated trigger is coupled via the multi-instrument trigger bus cable as the trigger event to trigger all instruments in synchronism.