Aeroflex 2948B Betriebsanleitung PDF herunterladen (Seite 123)

LOCAL OPERATION

3-69

Assigning

The assignment of the incremental keys is shown in the display, along with the step value.

To assign a parameter to a pair of keys, first select the parameter as if to change the value using

the data input keys, but rather than entering a new value press the orange [ALT ∆] key. Now enter

the value of the step to be incremented at each keypress, followed by the correct terminator key.

For example to assign the FREQ [×] and [Ø] keys to AF generator 1 in the Tx TEST mode and to

step up or down by 500 Hz steps, follow this procedure:-

From the Tx TEST display press the [Audio Gen] key.

Use the [Gen 1/Gen 2] key to select AF1

Press the orange [LEVEL] key.

The

LEVEL legend following AF1 will be highlighted.

Press the orange [∆ INC] key, followed by [5] [0] [0] and the [Hz] terminator key.

The display will show the legend

Increments

AF1 FREQ: 500 Hz

Now each press of a FREQ [×] or [Ø] key will increase or decrease the output frequency of AF

generator 1 by 500 Hz.

Points to note are:-

Each press of a FREQ [×] or [Ø] key will be effective from the current point. Thus if the

frequency of the generator in the above example has been incremented to

1,500 Hz and then

adjusted by use of the variable control (or the data entry keys) to

1,495 Hz, the next incremental

step down will produce a frequency of

995 Hz.

The assignment and value of a incremental setting will be retained, with the mode setup, when a

different mode is selected or the Service Monitor is powered down. This is of particular note

when assigned to the AF generators as they are also the modulation generators within the Rx

TEST mode and the AF generators within the AF TEST mode.

The incremental keys cannot be used when in the Dx TEST mode.

Use within spectrum analyzer mode

The SPEC ANA mode makes use of the FREQ [×] and [Ø] keys for span adjustment. The span is

ranged up or down in a 1, 2, 5 sequence, from 1.0 kHz to 1.0 GHz.

Adjustment to the span by these keys is linear about the center frequency and will not adjust below

zero or above the top frequency limit.

When the

Centre legend is highlighted the FREQ [×] and FREQ [Ø] keys will increment the

center frequency by the value last set up in the TxTEST mode.

The LEVEL [×] and [Ø] keys adjust the reference level of the spectrum analyzer in either 2 dB or

10 dB steps depending on the setting of the reference level vertical range.

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