NX-700/700H

NX-700/700HCIRCUIT DESCRIPTION+B +BF4015AD401DETSBCQ401INVQ404SB SW/OVRBIC403AVRF5012AQ40780T SWSBSB80C80TFinal AmpAudio Amp, Display BlockPA connectorD_Sub 25Pin connectorInternal OptionDisplay BlockTX circuitIC405DC/DCQ41250MC SW50MCRS-232C DriverQ40880R SW80RTXCRX circuitIC408AVRSBCQ416SW33A33A-2ASIC (Analog)Audio circuitIC410DC/DCIC404AVR150C50CRXCAssist, Tune circuitVCO, Internal Option,I/O expander, FM ICIC401DETIC402AVR/BINTIC409AVRQ41133BU SW15M33MASIC, DSP coreASIC, DSP I/OFlash memory33BUSRAM, RTCCN405Q40950R SWIC406AVR50R33CRX circuitRXCTCXO, PLLIC506DETMCU ResetIC407AVR33GPSInternal OptionFig. 88. Signaling Circuit8-1. Encode (QT/DQT/DTMF/MSK/2TONE)Each signaling data signal of QT, DQT, DTMF and MSK isgenerated by the DSP circuit, superposed on a modulationsignal and output from IC510. The modulation balance ofthe QT/DQT signal is adjusted by the D/A converter (IC712)and the resulting signal is routed to the modulation input ofthe VCO and VCTCXO (X1). The each deviation of the TXQT, DQT, DTMF and MSK tone is adjusted by changing theoutput level of the IC510 and the resulting signal is routedto VCO and VCXO. The RX DTMF tone is routed to the receiveaudio signal system, and is output from the speaker.9. Compander CircuitThe term “compander” means compressor and expander.The compander reduces noise by utilizing a compressorand an expander. The NX-700/700H contains DSP (IC502) toperform this operation. The NX-700/700H compander canbe turned on or off using the FPU.8-2. Decode (QT/DQT/DTMF/2TONE/MSK)The audio signal is removed from the FM detectionsignal sent to the DSP circuit and the resulting signal is decoded.22