Tektronix 2715, Руководство пользователя

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Getting Started
2–14
2715 User Manual
CAUTION. The total signal power (that is, all signals on-screen or off added
together), not just the signal of interest, must remain below +70 dBmV. With a
small span, it is also possible to reduce the attenuation to view a low level,
on-screen signal while inadvertently allowing an off-screen, high-level signal to
saturate the mixer, causing spurious responses and possibly even damaging the
mixer.
4. Press [INPUT] [9] to turn on the built-in calibrator.
NOTE . The amplitude of the internal calibrator is 18.8 dBmV. This places the
peak level at the top graticule line with the reference level set at 18.8 dBmV and
0 dB internal attenuation.
To measure the calibration signal, you are going to use the three primary controls
on the spectrum analyzer. These are located in the central dark gray function
block and are shown in Figure 2–4. The three primary controls and the FREQ/
MKRS knob to the left are the controls you will use most often. In general, you
can make most measurements with only these controls, although you will find
that other controls and menu features enable you to make many measurements
more quickly and conveniently.
Decrease
Change span/div in
1–2–5 sequence
Selects
frequency for
immediate
keypad entry
Selects reference
level for immediate
keypad entry
Decrease Increase
Change frequency in
designated step size
Increase
Increase
Decrease
Change reference
level in 1 dB or
10 dB steps
Selects span/div for
immediate keypad entry
Figure 2–4: The Primary Controls
First, raise the displayed signal height by reducing the reference level. The
reference level represents the signal power needed to deflect the displayed
spectrum to the top graticule line. The 2715 provides several methods of directly
changing the reference level. The most convenient method is to press the
arrow keys.