Tektronix 11801C User Manual page 319

11801C User Manual
The input diodes in sampling heads are susceptible to damage from electro
static discharge and from voltage levels that are outside the range printed
on the face of the sampling head. Always wear an antistatic wrist strap
connected to the ANTISTATIC CONNECTION on the 11801C when you are
making connections to a sampling head or handling the device under test.
The channel indicator light can have three states: off, on steady, or blinking.
The operation of the channel indicator light is controlled by the Selected
Channel Identification selector, located in the Sampling Head Fnc's
pop up menu. The Selected Channel Identification selector has two modes,
Flash or Quiet. Flash is the default mode. When Selected Channel Identifica
tion is set to Flash, the operation of the SELECT CHANNEL button is as
follows:
H If the yellow light is off, the channel is not displayed. Pressing the button
creates a trace of that channel.
H If the yellow light is on steady, the channel is displayed but is not part of
the selected trace. Pressing the button selects that trace, causing the
light to blink.
H If the yellow light is blinking, the channel is part of the selected trace.
Pressing the button will remove all traces displaying that channel.
When Select Channel Identification is set to Quiet, blinking is suppressed
and the SELECT CHANNEL button operates as follows:
H If the yellow light is off, the channel is not displayed. Pressing the button
creates a trace of that channel.
H If the yellow light is on, the channel is displayed. If the channel is not the
selected channel, pressing the button will make it the selected channel.
If the channel is the selected channel, pressing the button will remove all
traces displaying that channel.
You can always identify the selected channel by displaying the
Trace Status menu using the More... selector in the WAVEFORM
menu.
Setting Select Channel Identification to Quiet minimizes displayed jitter at
horizontal settings of 50 ps/div or less.
The red TDR ON light indicates whether or not the sampling head is send
ing out a TDR (Time Domain Reflectometry) step through the signal connec
tor. You control the TDR function from the Sampling Head Fnc's pop up
menu (see Controlling TDR and Smoothing Functions).
NOTE
Sampling Heads
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