Kenwood TM-V7A Service Manual

CIRCUIT DESCRIPTION
Squelch Circuit
The squelch control angle is read into the panel section
microprocessor and converted from analog to 6-bit digital.
For adjustment mode, on the main unit side, the threshold
ievel signal is received and the SQ voltages (SQV and
SQU) at that time are stored into the microprocessor. The
Shift Register Circuits
The TX-RX units have two shift registers (IC19 and
IC20: BU2090FS) and carry out the control below.
@1C19 Control
microprocessor calculates the squelch release voltage
using this voltage as the reference. This voltage and the
panel section squelch control voltage are compared and the
TM-V7A/E
squelch switched on and off.
@1C20 Conirol
Pin No. Name Function
1 Vss GND
2 DATA Serial data input
3 CLOCK Clock
4 VRX 144 8RSW
5 UTX 430 8TSW.
6 VIX 144 8TSW.
7 AM2 AGC control
8 AMi AGC control
9 V14RSW 144 band reception power control
10 V43RSW Sub 430 band reception power control
11 VRX 430 8RSW
12
13 U43RSW 430 band reception power control
14
15 Ui4RSW Sub 144 band reception power control
VDD 5V
— o
Pin No. Name Function
1 Vss GND
2 __| DATA Serial data input
3 CLOCK Clock
4
5 AM SW AM switching
6
7
8 USHIFT UHF VCO shift
9 FAN Fan control
10 VPLL VCO high-speed lock (VHF)
11 VSHIFT VHF VCO shift
12 AGC AGC switch
13 VAIP VHF AIP switch
14 UAIP UHF AIP switch
15 UPLL VCO high-speed lock (UHF)
16 VDD 5V

Kenwood TM-V7A Specifications

General Specifications

VHF frequency range	144~148MHz
UHF frequency range	438~450MHz (U.S.A/Canada)
Antenna impedance	50Ω
Usable temperature range	-20°C to +60°C (-4°F to +140°F)
Power supply	13.8V DC ±15% (11.7~15.8V)
Grounding method	Negative-ground
Frequency stability	±3ppm (-10°C to +50°C)
Dimensions (W x H x D)	140 x 54.5 x 205.5 mm

Transmitter Specifications

High power output	50W (VHF) / 35W (UHF)
Mid power output	Approx. 10W
Low power output	Approx. 5W
Spurious emissions	-60dB or less
Maximum frequency deviation	±5kHz
Audio distortion	3% or less (at 60% modulation)
Microphone impedance	600Ω

Receiver Specifications

Circuitry	Double conversion
Intermediate frequency (1st / 2nd)	38.85MHz / 450kHz and 45.05MHz / 455kHz
Sensitivity (VHF or UHF band)	0.16μV or less (12dB SINAD)
Sensitivity (Sub VHF or UHF band)	0.25μV or less
Selectivity (-6dB)	12kHz or more
Selectivity (-60dB)	28kHz or less
Squelch sensitivity	0.1μV or less
Audio output	2W or higher (8 ohms, 5% distortion)
Audio output impedance	8Ω

Weight and Dimensions

Weight	1.2 kg (2.6 lb)
Dimensions (W x H x D)	5.51" x 2.15" x 8.09"