QCX assembly Rev 1.08
4
4.26 Alignment menu .............................................................................................................................................. 96
4.27 Test equipment ............................................................................................................................................. 100
5.
Circuit design ......................................................................................................................................................... 104
5.1
Block diagram and summary ......................................................................................................................... 104
5.2
Circuit diagram .............................................................................................................................................. 106
5.3
Synthesised oscillator.................................................................................................................................... 106
5.4
Transmit/Receive switch ............................................................................................................................... 107
5.5
Band Pass, Phase Splitter, QSD and pre-amps .............................................................................................. 108
5.6
90-degree audio phase shift ......................................................................................................................... 109
5.7
CW filter ........................................................................................................................................................ 110
5.8
Audio amplifier .............................................................................................................................................. 110
5.9
Transmit signal routing and PA driver ........................................................................................................... 112
5.10 Class-E Power Amplifier ................................................................................................................................ 112
5.11 Low Pass Filter ............................................................................................................................................... 114
5.12 Key-shaping circuit ........................................................................................................................................ 114
5.13 Microcontroller ............................................................................................................................................. 116
5.14 Optional GPS interface .................................................................................................................................. 119
5.15 In Circuit Programming (ISP) interface .......................................................................................................... 120
5.16 Test Equipment ............................................................................................................................................. 120
5.17 5V voltage regulator...................................................................................................................................... 123
6.
Fault-finding .......................................................................................................................................................... 123
6.1
Blank LCD or blocked LCD ............................................................................................................................. 123
6.2
No backlight at all.......................................................................................................................................... 123
6.3
A row of blocks appears on the top row ....................................................................................................... 124
6.4
DC voltage readings ...................................................................................................................................... 124
6.5
RF Power output check ................................................................................................................................. 126
6.6
Audible continuous clicking noise during receive ......................................................................................... 127
7.
Measurements ...................................................................................................................................................... 127
7.1
Equipment ..................................................................................................................................................... 128
7.2
Transceiver current consumption ................................................................................................................. 128
7.3
Transmitter power output ............................................................................................................................ 129
7.4
Class-E Power Amplifier drain waveform...................................................................................................... 130
7.5
RF envelope key-shaping .............................................................................................................................. 130
7.6
Low Pass transmitter harmonic output filter characteristics ....................................................................... 131
7.7
Band Pass receiver input filter characteristics .............................................................................................. 131
7.8
Quadrature Sampling Detector bandwidth .................................................................................................. 134
7.9
CW Filter response ........................................................................................................................................ 135
7.10 Unwanted sideband rejection ....................................................................................................................... 136
8.
Operation reference “cheat sheet”
..................................................................................................................... 137
9.
Resources .............................................................................................................................................................. 138
10.
Document Revision History ............................................................................................................................... 138
Содержание QCX 5W CW
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Страница 26: ...QCX assembly Rev 1 08 26 3 19 Install 20MHz crystal XTAL1 The engraving on this crystal is 20 000...
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