New Law 0f Physics in Radio Reception

Archampsys

As an inventor (in radio demodulation) of some thirty years standing, I announce a new law in radio communications theory.
The theory that multi-path conditions in FM and AM and digital radio can be described by the use of the Rayleigh function for the addition of sine wave carriers is invalid.
This long standing theory pre-supposes that numerous radio echoes add together to form an ensemble of vectors at different strengths and different delays around a specific carrier frequency. If the strong line-of-site ray is occluded, then the antenna receives a number of these rays which add together to form a Rayleigh distribution.
This is indeed what happens but the effects on the demodulation of a radio signal are completely different to what has been accepted in the past 100 or so years.
To understand what really happens you must take one incident ray and one reflected ray only and add these two vectors at a delay of 180 degrees (lamda/2) and a reflection strength of unity. (Lossless Reflection)
This is your starting point and is elementary and fundamental.
When you analyse what is called the delay equation for a modulated signal, the results are astonishingly simple and yet never seem to have been observed correctly in the past.
In AM, the carrier is removed, the modulation function is differentiated, and the amplitude is reduced by the ratio of the modulation frequency to the carrier frequency times pi radians.
In FM, the carrier is also removed, the fixed amplitude carrier is converted to amplitude modulation by the differentiation of the modulation and the mean amplitude is reduced in strength by the ratio of the modulation frequency to the carrier frequency times pi radians.
Both these near identical results have a devastating effetc on the demodulation process.
In AM, the carrier is severely attenuated and the AM signal is converted to DSSC. This waveform cannot be demodulated reliably without the presence of a pilot tone. Envelope demodulation results in unintelligible distortion.
In FM, the position is even worse. The loss of the coherent carrier cause the phase of the carrier to change by 180 degrees every time the modulating signal changes sign. You hear a semi-infinite spike at every zero crossing of the signal, which again destroys the intelligibility.
Worse, there is a transition region or distance in space where this phenomena builds up which has been named the SCAM zone after DSSC AM-FM or DSSCAM-AM.
With a carrier at 100 MHz (3 m wavelegth) this zone can stretch from 3 mm wide to about 200 cm depending on the wavenumber of the delay.
This is the distortion mechanism you hear when you drive your car in city areas.
If you have a third echo, then you are saved. The first two will be busy annihilating each other, and the third will come along and save the day. It will be still at or near the original strength of the of the incident and the reflected waves.
If you have a fourth echo then because of the impossibility of creating a SCAM zone with one incident and three reflecions you will have near perfect reception.
Thus the Rayleigh fading model which has been used (mistakenly) to mislead radio demodulation engineers for over 100 years is not a valid theory. The valid theory is the examination of the dual precise ray delay equations which leads to the complete opposite conclusion about multipath conditions of reception.
New technology has now evolved that can demodulate both AM, FM and digital transmissions under the above conditions. More later.
Archie Pettigrew
ampsys@paisley.ac.uk