Acquisition
TDS 620A, 640A & 644A User Manual
2Ć21
The digitizing oscilloscope supports three acquisition modes:
H Sample
H Envelope
H Average
Bandwidth refers to the range of frequencies that an oscilloscope can acĆ
quire and display accurately (that is, with less than 3 dB attenuation).
You can set different bandwidths with the digitizing oscilloscope. Lower
bandwidth settings let you eliminate the higher frequency components of a
signal. The TDS 600A series offers Full (500 MHz), 100 MHz, and 20ĂMHz
bandwidth settings.
You can couple your input signal to the digitizing oscilloscope three ways.
You can choose between AC, DC, or Ground (GND). You can also set the
input impedance.
H DC coupling shows both the AC and DC components of an input signal.
H AC coupling shows only the alternating components of an input signal.
H Ground (GND) coupling disconnects the input signal from the acquisiĆ
tion.
H Input impedance lets you select either 1ĂMW or 50 WĂ impedance.
NOTE
If you select 50 WĂimpedance with AC coupling, the digitizing
oscilloscope will not accurately display frequencies under 200ĂkHz.
Also, the optional P6205 probe automatically switches the input
coupling to 50 W. This setting is appropriate for active probes like
the P6205. If changing to a passive probe, or using any input signal
that is not from a 50 W system, be sure to switch the channel input
coupling to 1 MW.
See Scaling and Positioning Waveforms, on page 2Ć22.
See Acquisition Modes, on page 3Ć3.
Acquisition Modes
Bandwidth
Coupling
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