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| Exp Nr. | Details |
|---|---|
| 1 Simple AM TX/RX(click here for *.grc) |
In the simple AM experiment, we transmit
Janaganamana(click here *.wav)
using AM with
carrier frequency 100kHz. First of all, everything except the
final audio output is in digital mode, i.e. they are discrete time
samples. The audio sink hardware draws out samples from the flowgraph
at the chosen clock rate (you can set this). We have chosen a sampling rate of 441k samples per second for this system. What it means is that values displayed on the computer are samples of the actual time waveforms at intervals of 1/441k second. On the other hand the audio card has chosen 44.1k rate. Thus, samples from the flowgraph are decimated by a factor of 10, before being given to the audio card. We do not use the throttle (or time-keeper) block in this flowgraph since the audio hardware is in use. Recall that the throtlle orchestrates the timing operations in such a way that the user feels as if the symbols are transmitted at the specified rate. |
| 2 Passband Tx-Rx(click here for *.grc) | In this experiment complex baseband data (Real+Imag) is upconverted to passband and transmitted. The real and imaginary part are taken as two audio files File1(click here) and File2(click here). These are picked from the internet. The passband data is then decoded at the receiver into the corresponding baseband with real and imaginary parts. The sum of the two signals is then fed to the audio player. |
Send suggestions and/or comments to: bsraj att ee . Better to use the Right to Information (RTI) act in the class than later.