Yaesu FT-101E User Manual

(4) AUDIO UNIT ( PBI315A4)
This module contains the microphone amplifier, receiver
audio amplifier, VOX amplifier and CW sidetane ascil
later. A speech signal from the microphone is fect to
the first MIC amplifier QL2SKI9GR FET from pin 3,
Input impedance of the MIC amplifier is 50 K ohms.
The signal, controlled in amplitude by the MIC GAIN
control between pin 3 and pin 4, 1% amplified by the
second microphone amplifier Qe, 25C372Y and applied
to the emitter follower QS, ZSCA72Y to be delivered
to the modulator unit fram pin &.
The receiver awdio signal from the AUDIO GAIN
contral is applied through pin 19 to 4 pre amplifier
Q9,25C1000, and amplified by integrated circuit Q8,
AN2I4. This stage, in turn, increases the signal to
speaker level. The audio power amplifier circuit
utilizes the OTL (output transformer less) circuit
and delivers 3 watts output to the speaker through
Dik 24.
The signal from the first microphone amplifier ts coupled
through the VOX GAIN control potentiometer VR1 to
VOX amplifier Q4, TAVO42M, The signal amplified
by G4 is fed to the VOX rectifier, The positive DC
output voltage of the rectifier is applicd to the gate
of the VOX relay control transistors G15, 2SK19¥
and Q6, 2SC373 causing them to conduct and actuate
the VOX relay RLT on the maim chassis. The collector
circuit of 6 is connected to. RLL through pin Is.
The ANTITRIP circuit provides a threshold voltage
to
prevent
the
speaker
Gutput
from
tripping
the
trans
ceiver into the transmit function. The receiver audio
VR. VR, Q, VR. VR, VR,
; fi é
q,— 6
ot
ay ?
0. ae ll }
e. ——-Q,
VRS to the antitrip amplifier 4, and fed to rectifiers
Dl and D2. 2S1555, Negatwe DC output voltage from
the recofier. connected to the gate of QS, reduces the
rain of the VOX -centrol transistor previdina the neces:
sary antitrip threshold, ANTITRIP control VES adjusts
the value of the antitrip voltage threshold so that the
loud Speaker output wil not produce excessive positive
DC output from the VOX. rectifier to exceed the neva
tive DC output from the antitrip rectifier and cause
the control transistor to actuate the relay, When speak
ing into the microphone normally the positive voltage
will exceed the negative antitrip voltage and actuate
the relay. VES pravides course adjustment for relay
sensitivity,
Relay hold time will be determined by DELAY control
VRa,
The tone oscillator GY, 2SC0'73 aperates when -the
MODE switch is in CW position, It is a phaseshift
oscillator operating at approximately 800 Hz. The tone
output is cativated by the keving cireuit and coupled
throuch SIDETONE LEVEL. control VR4 te the receiver
audio amphiier for sidetone monitoring 1m CW operation.
The output from Q7 is-also coupled ta the VOX amplifier
O4 for break-in CW eperabion
(5) MODULATOR UNIT (PBI184A)
The MODULATOR UNIT coantamns the carrier oscil:
lators; the ring modulator ¢circunt fer SSR. and AM
modulator. The carrier oscillator oscillates -‘enther 41¥38.5
KHz for USB or 31815 KHz for LSB, depending upon
TC, TC, Te, VR, a ce OE tin ¥R,
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PBI 184

Yaesu FT-101E Specifications

General

Brand	Yaesu
Model	FT-101E
Category	Transceiver
Language	English