Basic Theory Of Operation; Major Assemblies - Motorola APX 5000 Service Manual

Chapter 3 Basic Theory of Operation
This chapter discusses the basic operational theory of the ASTRO APX 5000/ APX 6000/
APX 6000Li radio, which is a wideband, synthesized radio available in the VHF (136–174 MHz),
UHF1 (380–470 MHz), UHF2 (450–520 MHz) and 764–870 MHz frequency bands. All ASTRO
APX 5000/ APX 6000/ APX 6000Li radios are capable of both analog operation (12.5 kHz or 25 kHz
bandwidths), ASTRO mode (digital) operation (12.5 kHz only) and X2-TDMA mode (25 kHz only).
3.1

Major Assemblies

The ASTRO APX 5000/ APX 6000/ APX 6000Li radio includes the following major assemblies
(See Figure 3-1.):
• VOCON Board – contains a dual-core processor which includes both the microcontroller unit
(MCU) and a digital signal processor (DSP) core, the processor's memory devices, an audio
and power supply support integrated circuit (IC), a digital support IC, and external audio power
amplifier.
• Transceiver (XCVR) Board – contains all transmit, receive, and frequency generation circuitry,
including the digital receiver back-end IC and the reference oscillator.
• Expansion Board
- Mace – contains the internal audio power amplifier circuitry, and a Type III secure IC.
- Mace with Apps – contains the internal audio power amplifier circuitry, a combination
Global Positioning System (GPS)/ Bluetooth 2.1 IC and support circuitry, a 3-axes digital
accelerometer, an e-MMC NAND flash, and a Type III secure IC.
• Top Display – 112 pixels x 32 pixels, transflective monochrome liquid crystal display (LCD).
• Control Top – contains five switches: On/Off & Volume Knob, a 16 position Channel/
Frequency Knob with concentric 2 position switch (for Secure Enable/Disable operation), a 3
position toggle switch for Zone Selection, and a push button switch used for Emergency calling.
The control top also includes an TX/RX LED that is solid amber upon receive, red on PTT, and
blinks amber on secure TX/RX.
• Front Display (Dual-Display Version only) – 130 pixels x 130 pixels, transflective color LCD.
• Keypad (Dual-Display Version Only) – Dual-Display version, Limited Kaypad Version has a
3 x 2 Menu keypad with 4-way navigation button, and Full Keypad Version has a 3 x 4
alphanumeric keypad.