Tektronix TDS 540

• 
  500 MHz maximum analog bandwidth.
• 1 Gigasample/second maximum digitizing rate (TDS 540) - 500 Megasamples/second maximum digitizing rate (TDS 520).
• Four-channel acquisition—the TDS 540 offers four full-featured channels;
  the TDS 520 offers two full-featured channels and two channels with
  limited vertical scale selections: 100 mV, 1 V, and 10 V.
• 
  Waveform Math—Invert a single waveform and add, subtract, and multiply
  two waveforms. On instruments equipped with option 2F, integrate or
  differentiate a single waveform or perform an FFT (fast fourier transform)
  on a waveform to display its magnitude or phase versus its frequency.
•  Eight-bit digitizers.
• Up to 15,000-point record length per channel (50,000-point optional).
• Full GPIB software programmability. GPIB hardcopy output. On instruments
  equipped with option 13, hardcopy output using the RS-232 or
  Centronics ports.
• Complete measurement and documentation capability.
• 
  Intuitive graphic icon operation blended with the familiarity of traditional
  horizontal and vertical knobs.