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LT51 Frequency Bandwidth
Frequency span
Press the
Turn the knob clockwise to increase, or anti-clockwise to reduce, the Span
Press the
The frequency span is updated on the frequency axis (in spectral mode) or
in the results area if in DMM mode.
The Span automatically sets the Resolution BW (see Resolution BW below)
Where the centre frequency is less than half the span selected, the start
frequency is set to 0 Hz and the measurement is baseband. Otherwise the
start, centre and stop frequencies are adjusted with the centre frequency.
NOTE: if the span selected together with the current centre frequency, would
cause the Stop frequency to exceed 2.4 MHz, the span is limited.
NOTE: For all measurement modes where the Interface is set to RTX, and the
LT51 Transmitter is ON sourcing a tone (eg. Return Loss, NEXT/Loss,
Balance etc.), the span will be automatically set to receive the current
Transmit Frequency. This does not apply when making selective
measurements or when sweeping.
The following table describes the relationship between frequency spans, marker
resolution and bandwidths used to measure signals in the LT51. The Res BW is
displayed in the centre of the CONFIG bar along the bottom of the display. The
LT51 uses the Hanning for numerical displays and Flattop for spectral displays.
Span
(kHz)
2,400.0
1,200.0
600.0
300.0
150.0
75.0
37.5
18.75
9.375
4.6875
Centre Frequency / Selective Level Meter
Press the
Turn the knob clockwise to increase, or anti-clockwise to reduce, the centre
frequency.
Press the
LT51 User Manual
key and then [f1] to select Span.
key (or any key) to clear the dialog box.
Marker
Resolution (Hz)
10,000
5,000
2,500
1,250
625
312.5
156.25
78.125
39.0625
19.53125
key and then [f2] to select Centre Frq.
key (or any key) to clear the dialog box.
Configuring the Tester
Res BW / ENBW (Hz)
Hanning
FlatTop
15,000
7,500
3,750
1,875
937
468
234
117
58
29
38,750
19,375
9,687
4,843
2,421
1,210
605
302
151
75
31
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