USER’S GUIDE TO SDR# (SDRSHARP).pdf

(428 KB) Pobierz
A USER’S GUIDE TO SDR# (SDRSHARP)
SDR# (aka “SDRSharp”) is an easy-to-use yet small and fast Software Defined Radio application for
Windows created by Youssef Touil with collaborative assistance from other talented software engineers.
SDR# is written in C#, a modern, general-purpose, object-oriented programming language developed by
Microsoft.
SDR# is intended as a Digital Signal Processing application for use with a wide range of RF hardware,
including:
•
•
•
•
•
•
•
•
•
•
SoftRock
FiFiSDR
FUNcube Dongle
SDR-4
LazyDog’s LD-1
SDR-IQ
SDR-14
RTL2832U / RTLSDR
Any sound card based SDR front end
Any ExtIO based SDR front end
More radios will be supported as interest demands. Latest information can always be found at the SDR#
website:
http://sdrsharp.com/
and on the #SDR channel on IRC, or via the mail reflector:
http://uk.groups.yahoo.com/group/SDRSharp/
The SDR# human interface is intuitive and flexible to use. “Run” and “Stop” buttons are found the very
top of the screen, along with the ability to select live data from a connected IQ stream or playback of
stored files.
The balance of the SDR# screen consists of three functional areas:
- Expandable control panels along the left-hand side
- Tuning controls and spectrum display at the top-right
- Waterfall display at bottom-right
- Controls for spectrum Zoom and waterfall Contrast along the rightmost edge
8/16/2012
1
EXPANDABLE CONTROL PANELS
SDR# comes with four standard control panels:
o
Radio
o
Audio
o
AGC
o
FFT Display
Each panel can be minimized by clicking on the “-“ sign, or expanded by clicking on the “+” sign.
RADIO:
The Radio panel includes information needed to configure, control, and tune the Software Defined Radio.
Here is a brief description of functions that are available:
1. MODE
Selections include Narrow FM (NFM), AM, Lower Sideband (LSB), Upper Sideband (USB),
Wide FM (WFM), Double Sideband (DSB), and CW with lower or upper-side offset (CW-L and CW-U)
NFM is used for all FM modes except FM broadcast, which is WFM.
2. FREQUENCY
This box shows the frequency that is actually being received. Direct entry is possible, but must be within
range of the center frequency that is presently set. Click the mouse anywhere in the spectrum display to
tune to that frequency.
3. CENTER
This box shows the center frequency that the RF front-end is tuned to. The combination of
FREQUENCY and CENTER displays can be used to tune SDR#. Once the CENTER frequency is set,
any signal within the spectrum display can be tuned, based on the sample rate of the RF front end. See
“Spectrum Display” for information on tuning using the mouse, otherwise center frequency (in Hz) can be
entered directly.
4. FRONT END
Various RF hardware options can be selected by clicking the down-arrow just to the right of the FRONT
END button. Available devices can be selected via the pull-down menu, and applicable defaults will be
displayed.
The FRONT END button brings up a menu containing any configuration options that are available for the
selected device.
5. FILTER TYPE, FILTER BANDWIDTH, FILTER ORDER
These three options allow customization of the window function, bandwidth, and order of the DSP filter
used by SDR#. Default options are chosen for nominal operation in each model, but can be changed as
desired, and the specified bandwidth will be shown as a highlighted area on the spectrum display. Filter
settings will return to the default values when SDR# is restarted.
6. SQUELCH
Clicking the box enables the Squelch function, which mutes the audio output until the received signal
exceeds the threshold value that is determined by the value in the box below. Lower values “loosen” the
squelch or decrease the signal level needed for audio to be heard. Higher values require stronger signals
before audio is heard. Squelch is available in AM and NFM modes only.
8/16/2012
2
7. CW SHIFT
This value determines the offset between transmit and receive frequencies in the CW modes for devices
having transmit capability.
8. SNAP TO GRID, STEP SIZE
These functions help to simplify tuning for channelized operation, and to customize the tuning response
of SDR# for all modes. A wide range of step size options can be selected from the pull-down menu to
accommodate various needs. For example, 12.5 kHz steps are used in aircraft communications, whereas
single sideband requires tuning in increments of 100 Hz or less. The Snap-to-Grid option forces the tuned
frequency to the nearest step size increment.
9. CORRECT IQ
SDR# has an original algorithm that compensates gain and phase imbalances between the IQ channels.
Without this compensation strong signals are mirrored with respect to the center of the spectrum, as can
be seen in the spectrum display of other SDR programs. This unique feature of SDR# should be left on
unless there is a reason to disable it.
10. Swap I and Q
Most RF front ends will present I and Q signals in the proper way, but if not, click this box to swap them
without changing hardware connections.
11. FM Stereo
When selected, stereo output is available in WFM mode (for broadcast FM listening)
12. Mark Peaks
Clicking this box toggles a visual indicator of peaks in the spectrum display as an aid for tuning.
USING THE SPECTRUM DISPLAY
8/16/2012
3
The above settings should enable basic SDR# Radio operation using RTL-SDR / RTL2832 USB DVB-T
dongle. Default frequency and mode settings are for FM broadcast where signals are strong and
something should be heard even with a limited antenna.
QUICK START:
Select the Front End, Enter a Center Frequency and Mode, then click “Start”. Default
settings should be sufficient for normal listening.
ANTENNA:
The short antenna supplied with DVB-T dongles provides poor reception and should be
replaced with a good VHF-UHF antenna mounted outdoors if possible. Low-loss RG-6/U coax is readily
available at reasonable price. Adapters can be purchased to adapt the “F” connector used on RG-6/U to
the PAL connector used on the dongle. Alternatively the supplied cable can be cut near the end and used
to make an adapter patch cable. Details for making inexpensive wideband VHF/UHF antennas such as
the discone can be found online. Old TV or scanner antennas, “rabbit ears”, etc can also be used.
8/16/2012
4
SPECTRUM DISPLAY
The spectrum display shows a continuous display of the RF spectrum. The amount of spectrum displayed
is a function of three factors:
1. The Sample Rate of the RF Front end. This determines the amount of RF spectrum that is
digitized and sent to SDR# for digital processing.
2. The setting chosen in the “FFT Display” control panel.
3. The setting of the “Zoom” slider to the right of the display area. Fully down, the amount of
spectrum displayed is the full amount that is provided by the RF Front End. As the slider is
moved up, the display zooms-in on the frequency presently tuned, showing more detail of the
signal being received, but less of the overall spectrum.
The relative amplitude of each signal can be estimated by comparing the height of each peak. With
practice one can quickly identify the different modulation types, based on their appearance in the
spectrum display.
Ability to easily tailor the spectrum display adds a great deal of capability to SDR#.
The FFT setting determines the base resolution of the spectrum display. A fairly low FFT setting (such as
4096) provides adequate resolution for many purposes yet places a minimal burden on the CPU.
Increasing the FFT provides much greater resolution, but at the cost of increasing the load on the PC
CPU, with the highest settings requiring so much computational time that audio becomes choppy. The
general rule of thumb is to use as high a setting as needed for your purposes, but no more.
The zoom feature makes it easy to temporarily see more details without changing the base resolution. It
is analogous to an old-time newspaper photo, where a magnifying glass enables you to see the dots that
are always present in the image. Zooming-in on a signal makes it easier to tune to the exact center, and
to view a limited chunk of spectrum in more detail.
The mouse can be used to change the center frequency by clicking and dragging the background of the
spectrum display to the right or left. Clicking on any part of the display area will tune SDR# to that
frequency.
8/16/2012
5

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika:

Zgłoś jeśli naruszono regulamin