Product description

FCC ID: EUGDJ-V5T

Operational Description

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FCCID_26157

a arviarvie a db mseasas aan ns «tzx 1",, ~ E l « E Cl * ED I-]ZEI Feb 9, 1999 Reception System: Double super heterodyne 1"* IF: FM 39.15MHz WFM 13.35MHz 2°" IF: 450KHz 2. Front—End: VHF: Incoming signal from the antenna passes through duplexer FL301 and low— pass filter, then changed by band—switch D317, amplified by RF amplifier Q312. The signal goes into band—pass filter, band—switch D314 and finally added to the mixer I1C306. WFM radio: Incoming signal from the antenna passes through duplexer FL301 and low—pass filter, then changed by band—switch D317, amplified by RF amplifier Q318. Then same circuit as above the signal goes to IC306. UHF: Incoming signal passes same circuit as above, changed by band—switch D321, RF amplifier Q321, band—pass filter FL303, band—switch D322 and finally to mixer IC306. 3. Mixer The sum and difference of input signal and first local signal is made in mixer IC306, separated FM and WFM signal at FM switch D319. FM: FM reception is obtained by selecting 39.15MHz at crystal filter XF301, eliminating adjacent signals then amplified by first IF amplifier Q320. WFM: WFM is obtained by band—pass filter, selecting 39.15MHz, eliminating adjacent signals. ~First local signal passes VCO output, cushion amplifier Q202, then goes into the local input terminal of mixer IC306. The upper—side local is used for VHF and WFM, lower—side local for UHF. 4. IF FM: Amplified signal at first IF amplifier Q320 goes into 16 pin on IC307. Added signal and IC302‘s standard—buffer output picks up 12.9MHz signal and triple it with Q322, then with the signal that added to IC307‘s 1* pin, IC307‘s internal mixer

circuit obtains 450KHz 2"" IF signal. This 24 IF signal comes out of the 3" pin of IC307, filtered adjacent signal by ceramic—filter FL302, then goes into 1C307‘s 5* pin. This signal is detected by limit amp and quadretcher circuit inside the IC, then goes out from the 10* pin as an audio signal. WFM: WFM signal goes into IC310‘s 16 pin. Added signal and IC302‘s standard— buffer signal 12,9MHz is doubled at Q322, then signal that added to IC310‘s 2* pin is mixed at IC310‘s internal mixer circuit and converted to 13.35MHz 2" IF signal. This signal comes out of IC310‘s 4* pin, goes into ceramic—filter FL304 and filtered adjacent signal, then returns to IC310 through the 7* pin. Then this signal passes through limit amp and quadretcher detection circuit inside the IC then comes out of IC310‘s 9 pin as an audio signal. Squelch FM: IC307s 10pin AF output signal goes into IC307‘s 11* pin. This signal passes through noise—amp and filter circuit inside and goes out of IC307‘s 13*" pin. This signal is added to microprocessor IC1H‘s AJ/D port, and AF output is controlled on and off by IC1. WFM: IC310‘s 10 pin outputs S—meter signal. This signal is added to IC1‘s A/D port and then controlled by IC1. Audio FM/WFM: the selection of audio output signal is made by IC308 for FM, IC312 for WFM. Then AF output signal passes through active band—pass filter Q329, AF switch Q330 then adjusted the volume level by VR601. Adjusted signal goes into audio power amplifier IC3‘s 2"" pin, comes out of 6* pin then goes to speaker. VYCO VHF/FM radio VHF and FM radio bands‘ VCO is consist of Colpitts oscillator. D202, D204, L202, and L203 determine the frequency, by oscillating it at transistor Q201. Oscillated signal goes into cushion amp Q202, Q304 then PLL—IC302‘s 19* pin. UHF: Colpitts oscillator is also used. D206,D208,L204 determine the frequency and oscillated by Q203. The signal goes into Q202, Q304 then PLL—IC302‘s 2"*" pin. 8. PLL To control VCO‘s oscillating signal PLL—IC302 is used. IC1 microprocessor transmits serial controlling signal to IC302. IC302‘s standard frequency 12.9MHz is oscillated by crystal X301 internally.

VHF/FM radio: IC302 compares phase of IC1‘s control signal that is added to the 19*" pin of IC302 and standard 12.9MHz signal inside IC302; as a result if the difference is detected, IC302‘s 13pin charge—pump outputs pulse signal, convert it to DC voltage by active—filter, then added to VCO‘s D202 and D204‘s cathode to eliminate the difference, to obtain stable oscillation for the selected frequency. UHF: IC302 compares phase of IC!‘s control signal that is added to the 2 pin of IC302 and standard 12.9MHz signal inside IC302; as a result if the difference is detected, IC302‘s 8**" pin charge—pump outputs pulse signal, convert it to DC voltage by active—filter, then added to VCO‘s D206 and D208‘s cathode to eliminate the difference. ~ ] ll. ] ! l.fi MIC—Amp IC314 has 2 Op—Amp. Voice is converted to electronic signal by the microphone, then added to IC314. The output signal is amplified and pre— emphasized. VHF: output signal from the Mic—amp is adjusted for the MAX freq.deviation by VR302, and by added to VCO‘s D205 cathode, controls capacitance of oscillation circuit to obtain FM modulation. UHF: same as above, but VR301 for Max deviation adjustment and D207 for VCO. The signal oscillated by VCO goes into Q202, IC301, Q308 then power amplifier Q@306. Amplified signal is filtered with low—pass filter and duplexer to eliminate harmonics, then connected to the antenna.


Document Created: 2019-10-28 21:17:51
Document Modified: 2019-10-28 21:17:51
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