Kenwood TH-D74E Service Manual page 68

LEVEL DIAGRAM
5
Receiver Section
RF (51.2MHz, 145.95MHz, 223.55MHz, 439.95MHz)
-60.0dBm
-75.0dBm -67.5dBm
ANT
Filter 439.95MHz
ANT Q172
-73.5dBm
4
D181
SW
223.55MHz
-71.0dBm -53.5dBm
145.95MHz
Q179
3
-71.0dBm
LPF
51.2MHz
-81.0dBm
LPF
80.2MHz
2
Note1: The RF levels at each point, were measured with a spectrum analyzer through a 0.1uF capacitor. When the -60dBm standard signal generator by a no modulation from ANT connecter.
Note2: The IF level were measured with 145.95 MHz of RX frequency.
Note3: The AF levels were measured with an oscilloscope when 145.95MHz of RX frequency, -60dBm standard signal generator signal modulated by a 1kHz modulation frequency and a 3kHz deviation was input and the AF output was adjusted to 0.63V/8 0hm by the AF VR.
1
A B
-49.0dBm -50.5dBm -51.0dBm
BPF
Q171 Q281
A-BAND UHF RX Circuit
A-BAND LO1
-45.5dBm -50.5dBm -5.5dBm
BPF
Q192
B-BAND UHF RX Circuit
(VHF) -52.5dBm
(VHF) -42.5dBm
BPF
Q178
A-BAND VHF/220 RX Circuit B-BAND LO1
-5.5dBm
(VHF) -41.0dBm (VHF) -49.0dBm
(220) -41.5dBm (220) -45.5dBm
-40.5dBm
IC283
BPF
Mixer
Q193
B-BAND VHF/220 RX Circuit
-42.5dBm B-BAND IF (58.05MHz)
Q190 Q191
B-BAND HF RX Circuit
TXRX CONT
-65.5dBm
Q195 P171
FM Tuner RX Circuit
RF (80.2MHz)
C
(No.RA044<Rev.001>) 2-18
A-BAND IF
(450kHz)
A-BAND IF (57.15MHz)
-59.0dBm -46.5dBm 0.20Vrms
XF281 IC281
MCF IF IC
Q282
A-BAND LO2 (57.6MHz)
-23.5dBm
AF (1kHz)
0.10Vrms
B-BAND LO2 (57.6MHz)
-23.5dBm B-BAND LO3 (460.8kHz)
-11.5dBm
-56.0dBm -24.0dBm -48.5dBm
XF282 IC284 IC285 IC286
MCF IF IC Mixer Amp
B-BAND IF
(450kHz) B-BAND IF (10.8kHz)
IC674
BPF
FM Tuner IC
Q675
D E
2-18 (No.RA044<Rev.001>)
AF (1kHz)
TXRX CONT
14mVrms 0.80Vrms
IC880
Power Amp
IC707
Codec
-43.5dBm
IC702
Main CPU
F
0.63Vrms
Q881/883
SP
Mute
G