SNV-12 Operations Manual
4-7
4.6.4
Software Description
The Site Voter Module software is contained in flash memory and can be updated by the CPM
module whenever software changes are necessary. The SVM Module Flash is partitioned into
sectors. Bootloader code is programmed into one sector that is protected to prevent accidental
erasure. The actual application code is stored in its own sector. When the SVM boots up it
will look for valid application code in its Flash. If it finds application code it will copy it into
internal RAM and execute it. During system boot-up the CPM module will query each SVM
module to determine if the firmware is up to date. The CPM module contains the latest code
for all voter modules. If the CPM determines that the SVM needs updating it will reset the
SVM in bootloader mode and transfer new application code. The SVM updates its Flash with
the new code. When the update is complete, the CPM will reset the SVM so that it can load
and execute the new application code. The bootload step is performed only when the SVM
Module code must be updated (the CPM module checks the revisions at power-up or module
installation), and is skipped otherwise (see Section 8 regarding software updates).
The SVM Module software is responsible for all RX Audio-related signal-processing functions
in the SNV-12. These include Signal-to-Noise measurement (HF/AM mode), Noise
measurement (FM mode), pilot and guard tone detection, pilot and guard tone notching, and
audio delay. Input samples from the A/D converter are passed to the various software routines
for processing, and the resulting audio samples are sent back to the D/A converter.
Signal-to-Noise measurement is calculated based on the measured amplitude of the input signal
in various frequency bands. Pilot tones are detected using a Discrete Fourier Transform
specially adapted for tone detection, while notching of tones is performed using FIR digital
bandstop filters. Running the output samples through a variable size circular buffer before
sending them to the D/A converter provides audio delay.
4.6.5
Select/Norm/Disable Switch
This three-position toggle switch places the module in one of the SVM‟s three operating
modes. The Norm position allows the usual voting processes to take place. The Select position
causes a “forced vote” of the site as long as its COR state is currently active (as determined by
any of the methods described in Section 5.10), while the Disable position excludes the site from
voting. When the switch is set to Select (or the SVM-2 module is put into the Select Mode by
other means), the Voted LED will flash as a reminder. Similarly, the Fault LED will flash if
the SVM-2 is in the Disable Mode.
4.6.6
Transmit Select (TX SEL) LED
This yellow LED lights if the Voters Transmit Steering function has selected the site for
transmit. This means that this site will key if the Console PTT Input is activated.
Содержание SNV-12
Страница 12: ...SNV 12 Operations Manual 12 This page intentionally left blank ...
Страница 22: ......
Страница 32: ...SNV 12 Operations Manual 3 4 SNV 12 Figure 3 1 Outline Dimensions ...
Страница 75: ...SNV 12 Operations Manual 3 47 ...
Страница 113: ...SNV 12 Operations Manual 3 85 Figure 3 12 SVM 1 Remote Receiver Audio Input ...
Страница 120: ...SNV 12 Operations Manual 3 92 Figure 3 19 SVM 2 for Type I Signaling ...
Страница 121: ...SNV 12 Operations Manual 3 93 Figure 3 20 SVM 2 for Type II Signaling ...
Страница 122: ...SNV 12 Operations Manual 3 94 Figure 3 21 SVM 2 for Type III Signaling ...
Страница 123: ...SNV 12 Operations Manual 3 95 Figure 3 22 SVM 2 for Type V Signaling ...
Страница 125: ...SNV 12 Operations Manual 3 97 Figure 3 24 CIM 2 for Type II Signaling ...
Страница 126: ...SNV 12 Operations Manual 3 98 Figure 3 25 CIM 2 for Type III Signaling ...
Страница 127: ...SNV 12 Operations Manual 3 99 Figure 3 26 CIM 2 for Type V Signaling ...
Страница 130: ......
Страница 142: ...SNV 12 Operations Manual 4 12 End of Section 4 ...
Страница 145: ...SNV 12 Operations Manual 5 3 Figure 5 1 RX Audio Delay ...
Страница 172: ...SNV 12 Operations Manual 5 30 This page intentionally left blank ...
Страница 196: ...SNV 12 Operations Manual 6 24 This page intentionally left blank ...
Страница 202: ......