User's Manual
Table Of Contents
- Table of Contents
- Introduction
- The Hardware
- Installation
- Getting Started
- Inside the Excelsior
- Resizing the Application Window
- Drop-Down Menu Controls
- Tuning the Excelsior
- Receiver Selection
- Mode Selection
- Function Tabs
- Spectrum Scopes
- Recording Functions
- Attenuator
- Preamplifier
- S-meter
- Top Menu Bar
- File
- Options
- Auto-mute RX not in focus
- Enable second RX
- Filter Length
- Front Panel LED
- Display Offset
- Time
- Keyboard Shortcuts
- VSC Set-up
- Audio Buffering
- AMS Capture Range
- Audio Output
- Show Measurements
- Show Data Rates
- Of particular interest to many users will be the CPU load (excessive CPU load may cause sluggish behaviour or freezing of the computer), and Audio latency. Apart from DDC bandwidth, CPU load may be minimized by reducing the Demodulator filter length (...
- Note: When measuring sensitivity using SINAD, it is very important that the Audio Filter is enabled and the cut-off frequencies (and for FM measurements, also the de-emphasis) are set according to the specified test conditions. Proper audio filtering ...
- Show Waterfall Timestamps
- Calibration
- Hand-Off Receiver
- Color scheme
- Restore factory defaults
- Memory
- Scheduler
- Scanner
- Logger
- Plugins
- Power Switch
- Date and Time Display
- Appendix A – SDR and DDC Primer
- Appendix B – Troubleshooting
- Appendix C – USB Interface Diagnostics
- Appendix D – Dealing with Interference
- Appendix E – G39DDCi PCIe Card Connections
- Appendix F – Waterfall Spectrum Palettes
- Appendix G – Recording File Formats
- Appendix H – Compliance Declarations
- Appendix I – Safety Disposal
WiNRADiO G39DDC User’s Guide
40
In the AMS mode, there is a certain "capture range", a frequency range within
which the receiver will "capture" the signal and achieve synchronization. If you
are tuning to a new signal, this initial capture (“Tune capture range”) is initially
quite wide, within plus or minus 1.5 kHz (default value) from the actual signal
frequency, to enable easy tuning by pointing and clicking near the peak in the
DDC spectrum, or dragging the filter passband area in the demodulator
spectrum.
Once locked to a signal, the capture range automatically reduces (“Sync. lock
range”) to plus or minus 50 Hz (default value) from the signal frequency. The
reason for such reduction is to avoid “kidnapping" of the synchronization
frequency by a nearby strong signal if the carrier signal fades, as may happen
especially with long-distance reception, due to ionospheric effects.
Both the Tune capture range and the Sync. lock range values are user-
definable, under the Options | AMS capture range menu:
When the signal is locked in synchronization, this is indicated using a "lock"
symbol located in the top left corner of the frequency display: