User's Manual
Table Of Contents
- 4. - ST-3118 RF DESCRIPTION
- 4.1. Circuit Configuration
- 4.2. Receiver System
- 4.2.1. Front-end RF Receiver
- 4.2.2. ANALOG Audio Processing
- 4.2.3. Virtual Squelch Circuit
- 4.2.4. Virtual VOLUME CONTROL
- 4.2.5. Sub audio signaling
- 4.2.6. ANALOG AUDIBLE SIGNALING
- 4.2.7. DIGITAL AUDIO PROCESSING
- 4.3. Transmitter System
- 4.3.1. ANALOG TX SIGNAL
- 4.3.2. DIGITAL TX AUDIO:
- 4.3.3. Drive and Final Amplifier Stages
- 4.3.4. Automatic Transmit Power Control
- 5. ST-3118 ALIGNMENT
- 5.1. Introduction
- 5.2. ALIGNMENT:
- 5.3. Required Test Equipment
- 5.4. Alignment Procedure
- 5.4.1. GENERAL ALIGNMENT CONSIDERATIONS:
- 5.5. MAIN RADIO ALIGNMENT
- 5.6. TRANSMITTER ALIGNMENT:
- 5.6.1. Main Clock alignment:
- 5.6.2. Transmit Power alignment:
- 5.6.2.1. High POWER LEVEL ALIGNMENT
- 5.6.2.2. Mid POWER LEVEL ALIGNMENT
- 5.6.2.3. LOW POWER LEVEL ALIGNMENT
- 5.6.3. ANALOG MAXIMUM DEVIATION
- 5.6.4. Modulation Gain alignment:
- 5.6.5. FDMA DATA MODULATION alignment:
- 5.6.6. TDMA DATA MODULATION alignment:
- 5.6.7. EIA tones Level Alignment:
- 5.6.8. DTMF signaling level alignment:
- 5.6.9. DCS signaling alignment:
- 5.6.10. CTCSS signaling alignment
- 5.6.11. FSK signaling alignment:
- 5.7. RECEIVER ALIGNMENT
- 5.7.1. DISCRIMINATOR GAIN
- 6. COMPLIMENTARY USER ALIGNMENT
- 6.1. OPTION ALIGNMENT:
- 6.1.1. ANALOG Microphone gain:
- 6.1.2. ANALOG External Mic Gain:
- 6.1.3. Analog AGC
- 6.1.4. DIGITAL AGC
- 6.1.5. MINIMUM VOLUME LEVEL:
- 6.1.6. SQUELCH LEVEL:
- 6.1.7. DISABLE RF POWER
- 7. RADIO APPEARANCE ALIGNMENT
- 7.1. DISPLAYS AND LEDS:
- 7.1.1. Auto backlight delay alignment:
- 7.1.2. Power on Text:
- 7.1.3. Leds:
- 7.2. Tones
- 7.3. ANNUNCIATION
ST-3118D SM R 1.1 SMARTRUNK SYSTEMS, INC.
9
analyzes the expected signaling
programmed on the current
channel table.
In case of not any additional
signaling must be decoded, or the
signal has been detected, the main
processor (U13) asks to the audio
processor (U12) to open the audio
path, unmuting the audio amplifier
(U8).
4.2.4. Virtual VOLUME CONTROL
The potentiometer position (R15 –
front board) is measured by one
analog to digital converter on the
audio processor (U12), and then the
information is reported to the main
processor. The firmware
immediately adjusts the audio
processor path gain to get the
appropriate overall circuitry volume
control.
Minimum volume, emergency and
private audio level are controlled
only by software overriding the
information received from the DAC
on U12.
4.2.5. Sub audio signaling
Received sub audio signaling, as
CTCSS and DCS, are received and
processed by the receiver (U2) then
detected on the audio processor
(U12). Once decoded, the sub audio
signaling is reported to the
processor where the firmware
compares it with the programmed
into the current channel
programming.
If the received signaling matches
the channel programming, then the
main processor (U13) requests the
audio processor (U12) to open the
audio patch.
4.2.6. ANALOG AUDIBLE SIGNALING
DTMF signals, MDC1200 and tone
signals are processed and decoded
by the audio processor (U12).
Decoded information or received
tone is reported to the main
processor (U13).
4.2.7. DIGITAL AUDIO PROCESSING
Digital received information is
processed by the receiver DSP (U2)
then delivered to the audio
processor (U12), which includes a
high-speed modem.
Data decoded by the modem is
transferred to the main processor
(U13) which de-encrypts the
information, checks the integrity,
correct the wrong bits and extract
the audio information form the
received frame.
The portion of the data received,
error free, is moved to the vocoder
(U14).
The vocoder re-builds the audio
from the compressed data then
applies filters, adjust the volume
RECEIVER
[U2]
AUDIO
PROCESSOR
[U12]
AMPLIFIER
[U8]
MAIN
PROCESSOR
[U13]
VOCODER
U14]
Figure 3: Digital Receiver Audio Path Block Diagram