Low distortion and high signal to noise ratio modulation and demodulation for both the AM and FM cases is possible, but several issues need to be recognized, among them: Filter characteristics, modulator and demodulator static and dynamic linearity, and topologies for modulators and/or demodulators. Approaches will be outlined which have resulted in successful achievement of distortion levels under 0.1% for AM and under 0.02% for FM, with signal to noise ratios of 80 to 90 decibels for AM and 70 to 80 decibels for FM. Better signal to noise ratios may be obtained at the sacrifice of distortion level. Distortion in amplitude modulators and demodulators is shown to be increased by processing passband amplitude asymmetry, and in frequency modulators and demodulators, by nonlinear phase response, as well as by modulator and demodulator amplitude distortion. A DFT (discrete Fourier Transform) approach is shown which can analyze the low-frequency theoretical distortion, and an example is given using the FM quadrature detector.
Click to purchase paper as a non-member or you can login as an AES member to see more options.
No AES members have commented on this paper yet.
To be notified of new comments on this paper you can
subscribe to this RSS feed.
Forum users should login to see additional options.
If you are not yet an AES member and have something important to say about this paper then we urge you to join the AES today and make your voice heard. You can join online today by clicking here.
