Agc (Automatic Gain Control) - Yaesu FT-950 Operating Manual

T
OOLS FOR
The AGC system is designed to help compensate for fading and other propagation effects. The AGC characteristics can be
individually set for each operating mode. The basic objective of AGC is to maintain a constant audio output level once a
certain minimum threshold of signal strength is achieved.
Press the [ AGC ] button repeatedly to select the desired
receiver-recovery time constant. You will observe the AGC
status notation in the AGC column of the Block Diagram
Display on the display, denoting the AGC receiver-recov-
ery time currently in use. For most operations, we recom-
mend the "AUTO" mode. Additionally, you may disable
the AGC by pressing and holding in the [ AGC ] button for
one second.
B D
LOCK IAGRAM
N :
OTE
Pressing the [ AGC ] button allows selection of the desired
receiver-recovery time constant. Normally, the "AUTO"
selection is satisfactory for most situations, but in the event
of operation on a crowded band where you wish to receive
a weak signal, you may wish to change the setting to FAST.
The AUTO mode selections are:
O M
PERATING ODE
LSB
USB
CW
AM
FM
RTTY
PKT ( FM )
PKT ( LSB )
A :
DVICE
The AGC selection will be memorized independently
on each VFO stack of VFO-A and VFO-B.
If the AGC receiver-recovery time is set to "Off" by
pressing and holding in the [ AGC ] button, the S-meter
will no longer deflect. Additionally, you will likely
encounter distortion on stronger signals, as the IF am-
plifiers and the following stages are probably being
overloaded.
Q :
UICK POINT
Several aspects of AGC performance may be configured
via the Menu. However, because AGC can have such a
profound impact on overall receiver performance, we gen-
erally do not recommend any changes to the AGC Menu
selections until you are thoroughly familiar with the per-
formance of the FT-950.
FT-950 O
PERATING
C
OMFORTABLE AND
AGC ( A
UTOMATIC
D
ISPLAY
AUTO AGC S
ELECTION
SLOW
SLOW
FAST
FAST
FAST
SLOW
FAST
SLOW
M
ANUAL
E
FFECTIVE
)
G C
AIN ONTROL
Block Diagram Display
[ AGC ] Button
T :
ERMINOLOGY
Automatic Gain Control, or AGC, is a circuit that senses
the incoming signal strength, and then limits the gain of
the RF and IF stages to keep the output audio volume at a
more-or-less constant level. AGC also protects the RF, IF,
Audio, and DSP stages from overload, as it limits the sig-
nal strength that is allowed to flow, irrespective of the in-
put signal level.
R
ECEPTION
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