Controls,  Connectors,  and Indicators
CH  1  AND  CH  2  VOLTS/DIV  VAR  Controls—Allow the  CH  1  and 
CH  2  vertical  deflection  factors  to  be  increased  up  to  at  least  2.5 
times.
Vertical  deflection  factors  are  greater  than  the  VOLTS/DIV  switch 
setting when the UNCAL indicator is lit and a greater-than symbol  (>) 
is  displayed  to  the  left  of  the  associated  VOLTS/DIV  readout.  The 
VOLTS/DIV settings are calibrated when the VAR control is in the fully 
clockwise  (detent)  position.
UNCAL Indicator—Lights when either CH  1  or CH 2 VOLTS/DIV set
ting  Is  uncalibrated  (variable function  in  effect).
SCOPE  BW  Button—Reduces  the  bandwidth  of the  vertical  deflec
tion  system  and trigger system to  20  MHz when the  button is  lit.  The 
full vertical deflection bandwidth is available when the SCOPE  BW but
ton Is  not  lit.
CH  2  INVERT  Button—Inverts  the  Channel  2  input  signal  when  the 
INVERT  button is lit.
The  Channel  2  input  signal  in  ADD  mode  and  the  Channel  2  trigger 
signal pickoff are also inverted.  A down-arrow symbol is displayed be
tween the Channel 1  and Channel 2 VOLTS/DIV readout when the IN
VERT  mode  is  on.
COUPLING  Buttons—Select the  method of coupling input  signals to 
the  Channel  1  and  Channel 2  attenuators.
GND—Disconnects the input signal and grounds the input of the asso
ciated  vertical  attenuator  to  provide  a zero  (ground)  reference  volt
age display.
The COUPLING  switch is  In the  ground  position when the  AC and the 
DC buttons are not lit.  A ground symbol  ( rh  )  is displayed to the right 
of the  associated VOLTS/DIV readout.
AC—Capacitively  couples  the  Input  signal  to  the  vertical  attenuator 
when the  AC button  is  lit.
Turning on AC Coupling turns off DC Coupling.  AC Coupling blocks the 
dc  component  of the  input  signal.  The  lower  -3  dB frequency  limit is 
10  Hz  or  less  when  using  either  a  IX  probe  or  properly  terminated 
coaxial cable;  it is  1  Hz or less using a compensated  10X probe.  With 
AC Coupling selected,  an AC  symbol  ( A; )  Is displayed to the right of 
the  associated  VOLTS/DIV  readout.  An  ac  symbol  is  also  displayed 
after the value readout  of a CURSOR VOLTS  measurement.
2245A  Operators
2-5