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R & S E K 8 9 5 / R & S E K 8 9 6
User Manual
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Passband Tuning and Notch Filter
3.1.10 Passband Tuning and Notch Filter
Note:
The frequency offset should be used for modu>
lation modes AM, CW, SSB, F7B, FAX and FM
only. In the ISB mode, the notch filter only has
an effect on the monitoring sideband. For the
SSB mode, the setting of negative filter fre>
quencies is not required.
If the LED assigned to the key NOTCH / PBT is il>
luminated, it is possible by using either the tun>
ing knob (R&S EK!895) or the step keys (R&S
EK!896) to
f offset the passband curve of the IF filter
with respect to the receive frequency
f adjust the notch filter frequency.
The currently effective offset or filter fre>
quency is indicated above the softkeys, e.g.:
PBT OFFSET x.xx KHZ
or
NOTCH A x.xx KHZ
Due to the offset and / or the filters, interfer>
ing receive frequencies, which are also in the
passband of the IF filter, can be suppressed.
Default Setting is activated (see 3.1.18.10):
The maximum (+bandwidth/2) or minimum
(>bandwidth/2) offset is determined by the cur>
rently effective IF filter bandwidth (see band>
width field). As soon as the effective offset is
b0, a black bar will appear in the status line
above PBT.
When changing one of the following parame>
ters the frequency offset is reset to 0.00:
f Frequency f Modulation mode
f Bandwidth f Channel
f BFO frequency
Each of the two notch filters may be adjusted
in the range of >5!kHz to 5 kHz. Only if a black
bar is visible above NOTCH in the status line,
will the notch filters be active. Cut in notch fil>
ters acc. to 3.1.20.2, if necessary.
When changing one of the following parame>
ters the notch filter A/B is set to 4.00 kHz:
f Frequency f Channel
f Modulation mode
Default Setting is inhibited
(see 3.1.18.11):
The offset may be adjusted in the range of
>5!kHz to 5 kHz.
3.1.10.1 Altering the Frequency Offset or
the Filter Frequency by Using the
Tuning Knob (R&S EK 895)
If the LED NOTCH / PBT is not illuminated, actu>
ate key NOTCH / PBT several times, as neces>
sary, until the desired frequency offset or filter
frequency is displayed. The indication will
change as follows:
PBT OFFSET x.xx KHZ
NOTCH A x.xx KHZ
NOTCH B x.xx KHZ
(x.xx = frequency offset or filter frequency last
entered)
In order to reduce the frequency offset or the
filter frequency turn the tuning knob counter>
clockwise.
In order to increase the frequency offset or the
filter frequency turn the tuning knob clock>
wise.
For passband tuning the reset to zero is
possible at any one time by pressing key CLR.
3.1.10.2 Altering the Frequency Offset or
the Filter Frequency by Using the
Step Keys (R&S EK 896)
If the LED NOTCH / PBT is not illuminated, actu>
ate key NOTCH / PBT several times, if need be,
until the desired frequency offset or filter fre>
quency is displayed. The indication will change
as follows:
PBT OFFSET x.xx KHZ
NOTCH A x.xx KHZ
NOTCH B x.xx KHZ
(x.xx = frequency offset or filter frequency last
entered)
6164.0717.02_01
> 3.24 >
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