Sony ICB-U655 Circuit Description

Frs(family radio service) tranceiver with 14 radio channels

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CIRCUIT DESCRIPTION of ICB-U655

ICB-U655 is a FRS(Family Radio Service) Tranceiver with 14 radio channels.

Part RX

Circuit system of ICB-U655(Part RX) is double conversion superheterodyne (lower

heterodyne). An incoming RF signal received through the Antenna goes through the

antenna switch (D1, D2, and D3) and is amplified at the RF Amplifier (Q1). The signal

is converted to a first Intermediate Frequency (IF:21.7MHz) at a first mixer (IC1). The

first Local Oscillator is a Phase Locked Loop (PLL) synthesized oscillator being varactor

tuned, which is variable between 440.8625MHz to 446.0125MHz in RX mode. The first

mixer is a Double Balanced Mixer (DBM). The first IF signal is amplified at a IF

amplifier (Q2) and is converted to the second IF of 450kHz at a second Mixer in the IF

IC (IC2). The second IF signal is demodulated at a FM demodulator in the IF IC (IC2).

The demodulated signal input to the Tone generator/detector IC (IC109) by which the

tone squelch circuit, de-emphasis, and HPF combine, and the tone squelch signal and

AF (Audio Frequency) signal are separated in IC109. The AF signal is amplified at an

AF Amplifier (IC102) and a Speaker connected to the AF Amplifier. Finally, the audible

signal is heard through a internal speaker.

1ch 462.5625MHz

2ch 462.5875MHz

3ch 462.6125MHz

4ch 462.6375MHz

5ch 462.6625MHz

6ch 462.6875MHz

7ch 462.7125MHz

8ch 467.5625MHz

9ch 467.5875MHz

10ch 467.6125MHz

11ch 467.6375MHz

12ch 467.6625MHz

13ch 467.6875MHz

14ch 467.7125MHz

FCC ID : AK8NTM30

Model : NTM-30

Page 1 FCC ID : AK8NTM30 Model : NTM-30 CIRCUIT DESCRIPTION of ICB-U655 ICB-U655 is a FRS(Family Radio Service) Tranceiver with 14 radio channels. 1ch 462.5625MHz 8ch 467.5625MHz 2ch 462.5875MHz 9ch 467.5875MHz 3ch 462.6125MHz 10ch 467.6125MHz 4ch 462.6375MHz 11ch 467.6375MHz 5ch 462.6625MHz 12ch 467.6625MHz...
Page 2 Model : NTM-30 Part TX Circuit system of ICB-U655(Part TX) is Narrow band FM with varactor modulation. The frequency is made with Phase Locked Loop (PLL) synthesized oscillator composed of VCO1 and IC3, and will take a route to Q3, Q4, Q5, Q6 (P.A), Low Pass Filter and finally to the Antenna for the transmission.
Page 3 FCC ID : AK8NTM30 Model : NTM-30 At the call The call operation starts when PTT is pushed at the standby mode. The call signal transmits automatically with an empty channel. The signal which is modulated by 1kHz and the tone signal is transmitted for several seconds. The 1kHz signal is generated by the System Controller and the tone signal is generated by IC109.