Kenwood TM-V7A Service Manual

TM-V7A/E
16
CIRCUIT DESCRIPTION
Mic Amp Circuit
The audio signals from the microphone are impedance
matched and enter AK2343 (IC507). AK2343 comprises a
2-stage amp, mute circuit, band pass filter circuit, limiter
circuit, and splatter filter circuit. It provides the audio signal
amplification. and preemphasis characteristic. The mute
circuit is used while transmitting DTMF signals and the like
from the microprocessor and during data transmission from
the packet terminal. The modulation circuits are directly
connected with the VCO variable-capacity diode for both
the 144MHz band and the 430MHz band and apply
frequency modulation.
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Microphone Key Input
The microphone UP/DOWN and function keys are con-
nected to the microprocessor analog input. The voltage
when a key is ON operates the corresponding function.
Also, the key input interrupt circuit is for switching the power
ON/OFF with the microphone. When the DOWN, MR, and
PF keys are pressed, an interrupt is generated and the mi-
croprocessor is awoken from stop mode. However, with the
TM-V7A/E, the power key is on the microphone, so the set
is designed to switch on the main unit power only when the
PF key is pressed and other interrupts are ignored.
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Fig.15 Microphone key input circuit

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"