Frequency Configuration - Kenwood TM-V7A Service Manual

TM-V7A/E
CIRCUIT DESCRIPTION
Frequency Configuration
The TM-V7A/E has separate VHF band and UHF band
PLL and intermediate frequency units, so simultaneous 2-
band reception is possible. There is also a VHF sub-
receiver for receiving VHF band signals with the UHF
section and UHF sub-receiver for receiving UHF band
signals with the VHF section.
The 144MHz band receiver is mixed down with the first
local oscillation 182.85 to 184.845MHz (E), 182.85 to
186.845MHz (K, M) to form the first intermediate frequency
of 38.85MHz. It is further mixed down with the second local
oscillation 38.4MHz to obtain the second intermediate
frequency of 450kHz.
The 430MHz band receiver is mixed down with the first
local oscillation 384.95 to 394.945MHz (M, E), 392.95 to
404.945MHz (K) to form the first intermediate frequency. of
45.505MHz. It is further mixed down with the second local
oscillation 45.505MHz to obtain the second intermediate
frequency of 455kHz.
The 144MHz sub-band receiver is mixed down with the
first local oscillation 189.05 to 191.045MHz (E), 189.05 to
193.045MHz (K, M) to form the first intermediate frequency
of 45.05MHz. This output is input to the UHF receiver No.2
intermediate frequency section to obtain 455kHz.
The 430MHz sub-band receiver is mixed down with the
first local oscillation 391.15 to 401.145 MHz (M, E), 399.15
to 411.145MHz (K) to form the first intermediate frequency
of 38.85MHz. This output is input to the VHF receiver No.2
intermediate frequency section to obtain the second local
frequency of 450kHz.
Thus, the 144MHz band and 430MHz band receivers
and sub-receivers all use double conversion.
The 144MHz band and 430MHz band transmitters both
have a PLL circuit with direct frequency division and direct
oscillation and amplify as is with a straight amp and transmit.
The main circuits are used to transmit signals even if a sub-
band is being used.
*A
*B *A
VY *A 450kHz
PA DRIVE [we PRE DRIVE Law
7 *A *A MIX 38.85MHz | ]
ANT RF RF AF
> > ~| MCF a
sw AMP AMP MIX. IF. DET AMP
SP
*C
be]
MIX
:
*D
MIC
PLL AMP
| MIC
12.8MHz
*B *B -
455kHz
PA he DRIVE 'e—) DRIVE [=e] PRE DRIVE ne
*B *B MIX 45.05MHz ' ]
ANT RF RF MIX. IF. DET
sw AMP AMP MCF
* A 144~147.995MHz : KM [_] 58.07MHz
144~145.995MHz : E __*E
*B 438~449.995MHz : K
430~439.995MHz : M,E
*C 182.85~186.845MHz : KM ~
182.85~184.845MHz : E
*D 399.15~411.145MHz : K
391.15~401.145MHz : ME *F PLL
*E 392.95~404.945MHz : K
384.95-~394.945MHz : ME
*F 189.05~193,045MHz : KM
189.05~191.045MHz : E
Fig.1 Frequency configuration