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Download TK-2180 - Multiradio SA
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TK-2180 CIRCUIT DESCRIPTION ■ High-speed data (5-tone) 7-2. Decode ■ Low-speed data (QT, DQT) The demodulated signal from the IF IC (IC200) is amplified by IC600 (1/2) and passes through an audio processor (IC607) and amplifier IC604 (1/2) and comparator IC604 (2/2) to remove a low-speed data. The CPU digitizes this signal and decodes the signal. The demodulated signal from the IF IC (IC200) is amplified by IC600 (1/2) and passes through a low-pass filter (IC607) to remove audio components. The signal is input to pin 128 of the CPU. The CPU digitizes this signal, performs processing such as DC restoration, and decodes the signal. ■ MSK The MSK input signal from the IF IC is amplified by IC600 (1/ 2) and goes to pin 5 of IC607. The signal is demodulated by MSK demodulator in IC607. The demodulated data goes to the CPU for processing. ■ High-speed data (DTMF) The DTMF input signal from the IF IC (IC200) is amplified by IC600 (1/2) and goes to IC607, the DTMF decoder. The decoded information is then processed by the CPU. During transmission and standby, the DTMF IC is set to the power down mode. IC607 IC600 AMP LPF HPF IC201 IC305 AMP COMPARATOR Battery +B is supplied via a 2.5A fuse from the battery terminal connected to the TX-RX unit. Power supply (+B) is applied to the four AVRs. IC402 supplies 5V (5M) to the control circuit. IC401 and IC403 supplies 5V to common circuits. IC406 supplies to the TX circuit, the RX circuit and common circuits. During transmission, 5TC becomes Low and Q406 is turned on to supply 5V (5T) to the TX circuit. During reception, 5RC becomes Low and Q405 is turned on to supply 5V (5R) to the RX circuit. The power supply voltage monitor IC (IC400) monitors power supply voltage (+B). If the voltage falls (less than 5.6V), the VOUT port goes “LOW” level, the CPU INT port also goes “HIGH” level, and the CPU stops. 10 HSDIN 128 LSDIN LPF DTMF DECODE XIN 8. Power Supply Circuit XOUT DTRLOAD STD DTRCLK DTRDO IC502 CPU X600 Fig. 13 Decode F400 +B RF power amp 2.5A Power SW D405 IC402 Q408 5M VOUT VIN CE VDD IC502 CPU VIN VOUT IC400 OUT IC405 Q407 RESET INT PSW D403 Q401 Q502 IC403 Q409 VIN VOUT CE 5C IC401 SAVE VIN VOUT CONT 5CNS 5R Q405 IC406 VIN VOUT CONT 5RC 5T Q406 5TC 12 Fig. 14 Power supply circuit
