To address the scarcity of radio frequency (RF) spectrum, the disclosed systems
offer unique ways to mitigate interference between television broadcasters (including
their direct audience and viewers served via cable television) and other concurrent
users of the RF spectrum, e.g. for one-way or two-way wireless communication. A
preferred embodiment makes use of the "framing" characteristics of the "letterbox"
video display format. RF emissions of the simultaneous RF spectrum user are keyed
"on" only or substantially only during the time intervals when the blanking intervals
and/or letterbox-border video lines are being scanned on the display, i.e. when
the potentially affected (interfered with) television display is in the letterbox-frame-scanning
portions of each video field. The concurrent uses may support services for voice
(including telephony, music etc.), data (including Internet, intranet, etc.); image
or control; fixed, portable, mobile or nomadic; narrowband, broadband or ultra-wideband;
radiodetermination, diathermy, etc.
