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WiNRADiO G303 Demodulators
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WiNRADiO G303 Demodulators
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G303 Demodulators are DSP software plug-ins which fit into the G303
control panel. All the last IF (intermediate frequency stage) and the
demodulation stage functions are performed in software. Having been
freed from hardware constraints, this brings about unprecedented level
of flexibility and performance to the receiver.
The G303 is being introduced with two demodulators, with others to
follow. The Standard Demodulator is included as a standard part of the
package, while the Professional Demodulator is optional.
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The Standard G303 Demodulator provides excellent performance with
minimum adjustable parameters, and facilities exceeding those of a
demodulator of a conventional shortwave receiver in this price range
(such as real-time spectrum scope).
The optional Professional Demodulator goes yet another step further
and offers additional modulation modes, and fully user-adjustable
demodulation parameters, complete with interactive block diagrams of the
internal structure of the demodulator, an additional dual real-time
spectrum scope with vector voltmeter, SINAD and THD measurement, and
many other facilities. This is a serious tool for a serious
experimenter. |
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G303 Standard Demodulator
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This demodulator is supplied as part of the G303 receiver package. It
features AM, AMS (synchronous AM), AMN (narrow band AM), LSB, USB, FM3
(3 kHz FM), FM6 (6 kHz FM), FMN (15 kHz FM) and CW modes, with fixed
bandwidths.
There is a real-time spectrum scope which shows the actual situation
on the received band.
An interesting feature is Audio AGC (in addition to the existing
hardware IF AGC). |
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Clicking the Setup button, another window opens, making it possible to
adjust the necessary minimum number of parameters for optimum
performance:
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The user adjustable parameters include the sound card selection,
sampling rate (48000 samples/sec is recommended, 44100 can be also
used), and the sound card input gain.
A clipping (input level overload) indicator and a CPU usage meter are
also provided for the user's convenience.
With a minimum of initial set-up, the demodulator (and so the G303
receiver) are ready to go! |
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G303 Professional Demodulator
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This advanced demodulator is offered as an optional extra. It adds DSB
and ISB modes, additional Audio AGC settings and continuous IF bandwidth
adjustment (from 1Hz to 15 kHz). There are also user-definable IF
bandwidth preset buttons at the bottom.
Many more exciting facilities are hidden under the Setup
button: Optimized filter settings make it possible to increase the
receiver sensitivity typically by 2 dB on AM, SSB and FM; and by up to
10 dB on CW. |
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The left part of the Setup window is similar to the Standard Demodulator.
The right one contains some surprises: The demodulator parameters (such as
the digital filter length) can be adjusted by the user. There are separate
"tabs" for independent setting of each of the eleven demodulation modes.
Clicking on the View Demodulator Structure button discloses an
interactive diagram of the demodulator structure:
At the top there is a block diagram showing the structure of the
currently selected demodulator (each modulation mode has its own
demodulator). Below, there are also two spectrum analyzers. Left clicking on
any of the color points inside the block diagram will connect the left
spectrum analyzer to the associated point (the color of the point will
change to red). Right clicking will connect the right spectrum analyzer (the
point color will turn blue).
At bottom left, there is a Vector Voltmeter showing amplitude and phase
differences between the two selected points, at the cursor frequency.
There are also THD (total harmonic distortion) and SINAD
(signal-plus-noise-plus-distortion to noise-plus-distortion) meters, to
complement this unique instrument.
Specifications are subject to change without notice.
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