Motorola CDM1550-LS+ - Page 4

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2.3.4.3 Dual Tone Multiple Frequency (DTMF) Data ........................ ... 2-12
2.3.5 Receive Audio Circuits ......................................................................... 2-13
2.3.5.1
Squelch Detect ......................................................................... 2-13
2.3.5.2 Audio Processing and
Digital Volume Control ......................... 2-13
2.3.5.3 Audio
Amplification Speaker(+) Speaker(-) ........................... 2-14
2.3.5.4 Handset Audio ......................................................................... 2-14
2.3.5.5
Filtered Audio and Flat Audio ................................................... 2-15
2.3.5.6 RX Secure Audio
Option .......................................................... 2-15
2.3.5.7
Option Board Receive Audio .................................................... 2-15
2.3.6 Receive
Signalling Circuits ................................................................... 2-16
2.3.6.1
Sub-Audible Data (PLIDPL) and High Speed Data Decoder ... 2-16
2.3.6.2
Alert Tone Circuits ................................................................... 2-16
2.3.6.3 Voice Storage
Option ............................................................... 2-17
2.4
200 MHz Receiver Front-End ............................................................................. 2-18
2.4.1 Receiver Front End .............................................................................. 2-18
2.4.2 Receiver Back End ............................................................................... 2-19
2.5 Transmitter Power
Amplifier (PA) 25 W ..... ........................................................ 2-19
2.5.1 Power
Controlled Stage ...................................... .. ...... .. ....................... 2-20
2.5.2 Pre-Driver Stage ................................................................................... 2-20
2.5.3 Final Stage ....................................................................... .. ... ............... 2-20
2.5.4 Directional Coupler .. .............................................. .. .... ... ...................... 2-20
2.5.5 Antenna Switch ...... ................................... ........................................... 2-20
2.5.6 Harmonic Filter ..................................................................................... 2-21
2.5.7 Power
Control ...................................... ................................................. 2-21
2.6 Frequency Synthesis .......................................................................................... 2-21
2.6.1 Reference
Oscillator .................................................. .. ......................... 2-21
2.6.2 Fractionai-N Synthesizer ..............................
, ....................................... 2-22
2.6.3
Voltage Controlled Oscillator (VC0) ..................................................... 2-23
2.6.4 Synthesizer Operation .......................................................................... 2-24
2.7
700 MHz Receiver Front-End ............................................................................. 2-25
2.7.1 Receiver Front-End .........................
.. ................................................... 2-25
2.7.2 Receiver Back-End .............................
... .................... .................... ... .... 2-25
2.8 Transmitter Power
Amplifier (PA) 15 W ............................................................. 2-26
2.8.1 Power
Controlled Stage .................................... .............. .... ................. 2-26
2.8.2 Driver Stage ......................................................................................... 2-27
2.8.3 Final Stage .................................. .. .............. ... ................................... .. . 2-27
2.8.4 Antenna Switch .................................................................................... 2-27
2.8.5 Harmonic
Filter ... ........ ... .............. ... ................................... .. ................. 2-27
2.8.6
Bi-Directional Coupler .......................................................................... 2-27
2.8.7 Power
Control ....................................................................................... 2-27
2.9 Frequency Synthesis .......................................................................................... 2-28
2.9.1 Reference
Oscillator ............................................................................. 2-28
2.9.2 Fractionai-N Synthesizer ...................................................................... 2-28
2.9.3
Voltage Controlled Oscillator (VC0) ..................................................... 2-29
2.9.4 Synthesizer Operation .......................................................................... 2-31
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