19
TRANSMISSION CIRCUIT 03
ALC Operation when an External Device is Connected
The “Connection Block to an External Device for ALC Signal Input” diagram shows the connection block with an external
device when ALC signal is input from the external device to the TS-890S as well as changes in the output level with the
ALC voltage.
It employs a method that controls the TS-890S gain by using an ALC voltage output from an external device, but it
consequently serves to control the TS-890S transmit power. This operation is common for both linear amplifiers and
transverters. The gain level of the IF circuit in the TS-890S lowers when the ALC voltage input from the external device
falls below -4 V (default setting). The gain decrease also leads to reduction of the transmit power (ANT output and DRV
output); this serves for output control.
Linear Amp. etc.
Detection
Circuit
ALC
Circuit
ALC Terminal (REMOTE Connector 6th Pin)
DRV Terminal
TX Mixer
ALC AMP
ANT
TX SIGNAL
Fig. 20 Connection Block to an External Device for ALC Signal Input
Fig. 21
Changes in DRV Output Level with ALC Input Voltage
●
Operation on an ALC Signal Input from an External Device
Adjusting the microphone gain and carrier level to optimize the ALC meter needle deflection while no ALC signal is input
from an external device enables more feedback control for the ALC when an external ALC signal is applied. Therefore,
the increase causes the ALC meter needle to deflect wider. In this case, turn the
[PWR]
knob counterclockwise while
monitoring the ALC meter needle deflection or readjust the microphone gain and carrier level.