Tektronix TDS 400 Digitizing Oscilloscopes are portable instruments suitable for use in a variety of test and measurement applications and systems. Key features include: Four input channels on the TDS 420 and TDS 460 (two input channels on the TDS 410), each with a record length of 500 to 15,000 points and 8-bit vertical resolution. (Option 1M extends the maximum record length to 60,000 points.) Simultaneous acquisition of waveforms in all channels at the maximum digitizing rate of 100 Megasamples/second. All channels acquire at the full analog bandwidth of 150 MHz (TDS 410 and TDS 420) or 350 MHz (TDS 460) and all have the same features. Video triggering capabilities (with Option 5, Video Trigger). Full programmability and printer/plotter output. Advanced functions, such as continuously updated measurements. Specialized display modes, such as infinite and variable persistence. A unique graphical user interface (GUI), an on-board help mode, and a logical front-panel layout which combine to deliver a new standard in usability. Advanced waveform math (with Option 2F, Advanced DSP Math). Compute and display the integral of a waveform, the differential of a waveform, and the FFT (Fast Fourier Transform) of a waveform.