Selecting The If Filter Shape - Icom IC-905 Basic Manual

4
RECEIVING AND TRANSMITTING
Selecting the IF filter
SSB, CW, RTTY, and AM modes
The IC-905 has 3 IF filter passband widths for each
mode, and you can select them on the FILTER
screen.
You can set the IF filter to wide (FIL 1), mid (FIL 2), or
narrow (FIL 3).
1. Select the operating mode. (Example: USB)
2. Touch the filter icon for 1 second.
• Opens the FILTER (SSB) screen.
3. Touch the filter icon several times to select FIL 1
(wide), FIL 2 (mid), or FIL 3 (narrow).
4. Touch [BW].
You can reset to the default settings
by touching this key for 1 second.
• Selects the passband width mode.
5. Rotate to select the passband width.
L You cannot change the passband width in the FM,
FM-D, or DV mode.
L When you change the passband width, the Digital
Twin PBT setting value is reset to the center position.
L "BPF" is displayed when a band width less than 500
Hz is selected in the SSB, CW, or RTTY mode.
6. To close the FILTER screen, push
TIP:
• When you set the IF filter to FIL2 or FIL3 in the FM
mode, the transceiver will transmit in the FM narrow
mode.
• When you set the IF filter to FIL2 or FIL3 in the ATV
mode, the transmit filter width will narrow.
Mode
SSB
SSB-D
CW
RTTY
AM
AM-D
FM
FM-D
DV
DD
ATV

Selecting the IF filter shape

SSB and CW modes
You can set the IF filter shape for each mode.
1. Select the operating mode. (Example: USB)
2. Touch the filter icon for 1 second.
• Opens the FILTER (SSB) screen.
3. Touch [SHARP] or [SOFT].
.
4. To close the FILTER screen, push
• SHARP
This selection is to emphasize the passband width of the
filter. The filter has an almost ideal shape factor. Signals
that are out of the passband are extremely filtered out,
and it gives you better audio quality.
• SOFT
The filter shoulders are roundly formed as in analog
filters. This decreases noise components in the high and
low frequencies of the filter passband, and increases the
S/N of the target signal. These characteristics play an
effective role in picking up very weak signals. The shape
factor is retained, and the sharpness of the bandpass is
excellent.
4-6
IF filter Selectable range (steps)
FIL 1 (3.0 kHz)
50 Hz to 500 Hz (50 Hz)/
FIL 2 (2.4 kHz)
600 Hz to 3.6 kHz (100 Hz)
FIL 3 (1.8 kHz)
FIL 1 (3.0 kHz)
50 Hz to 500 Hz (50 Hz)/
FIL 2 (1.2 kHz)
600 Hz to 3.6 kHz (100 Hz)
FIL 3 (500 Hz)
FIL 1 (1.2 kHz)
50 Hz to 500 Hz (50 Hz)/
FIL 2 (500 Hz)
600 Hz to 3.6 kHz (100 Hz)
FIL 3 (250 Hz)
FIL 1 (2.4 kHz)
50 Hz to 500 Hz (50 Hz)
FIL 2 (500 Hz)
600 Hz to 2.7 kHz (100 Hz)
FIL 3 (250 Hz)
FIL 1 (9.0 kHz)
FIL 2 (6.0 kHz) 200 Hz to 10.0 kHz (200 Hz)
FIL 3 (3.0 kHz)
FIL 1 (15 kHz)
FIL 2 (10 kHz) Fixed
FIL 3 (7.0 kHz)
FIL 1 (150 kHz) Fixed
FIL 1 (17 MHz)
FIL 2 (10 MHz) Fixed
FIL 3 (5 MHz)
.