Most of you are familiar with Automatic Gain Control (AGC) that has been incorporated in some of the newer X10 modules. Other manufacturers of X10 compatible equipment have been incorporating AGC in their switches for a long time (Leviton).
Most of you also know X10 commands are sent as a series of signal bursts coupled to the powerline. Presence of a burst signifies a logic "1", and absence a logic "0". Noise near the X10 carrier frequency can fill in those blank frames, making it impossible for a receiving module to decode the command unless it includes some form of AGC to raise its detection threshold above the background noise level. That is why we have so much trouble with electronic devices that inject noise onto the powerline.
Because there is a huge installed base of X10 equipment that does not contain AGC, and X10 apparently has thrown in the towel on producing new equipment with AGC, I have been thinking about a different approach to this problem. Why not selectively attenuate the noise, but let the signals pass through. The X10 XPNR was their stab at this solution, but unfortunately that did nothing to attenuate noise inside the X10 bandpass. I developed the Tuned Signal Sucker to also attenuate that noise, but few people even expressed an interest in trying a beta unit.
I propose an Automatic Noise Control module that will severely load down ANY noise (even inside the X10 bandpass) except when a valid X10 signal is transmitted. When it receives a valid X10 “1” bit, it will switch off the attenuation, allowing the signal to propagate to the modules. The only requirement is that the signal itself would have to be at least a factor of two above the noise level for reliable detection. This small module could be plugged into any AC outlet, preferably on the circuit with the most noise. Or one could be plugged into an outlet on each phase near the distribution panel to attenuate all noise on both phases. The kit might cost about $30, and the assembled unit $20 more.
Comments?
Jeff
Author
Topic: Automatic Noise Control (ANC) (Read 9549 times)