I think you're right. The SCOTUS in United States v. Lopez ( see https://en.wikipedia.org/wiki/... ) ruled that Congress cannot constitutionally regulate who can walk into a school zone carrying while a gun, because this is not interstate - commercial activity. It seems likely the same reasoning would apply to walking into or out of a school zone at all. But who's going to challenge the constitutionality of this kind of law?
Lamarr invented "frequency hopping" while CDMA cellular and GPS use "direct sequence". Frequency hopping is just what it sounds like: a narrowband transmitter is continually retuned to a different radio channel. Unless the receiver tuning follows the same sequence at the proper times it cannot receive the transmission.
Direct sequence XORs a narrowband signal with a high speed pseudorandom "chip" sequence, and the receiver undoes this operation by XORing it again by the same sequence properly synchronized in time. It closely resembles a keystream-type encryption system, though the "keystream" is not necessarily secret. The main difference is that direct sequence is a wideband signal while, at any instant, a frequency hopped signal is still narrowband.
Each method has advantages. Frequency hopping can be especially resistant to strong narrowband jamming, so it's a favorite of military systems (Lamarr's intended use). Direct sequence is easier to use with coherent modulation so it tends to use transmitter power more efficiently, and it can often provide precise timing and positioning as a side benefit. Or, in the case of GPS, as its primary purpose.
While CDMA mobile phones were very important in the 1990s and 2000s, it is now being replaced with LTE (Long Term Evolution), which uses OFDM - Orthogonal Frequency Division Multiplexing. So do many other modern terrestrial digital communication systems including DSL, HD Radio, DVB-T (but not ATSC), WiFi and DRM (Digital Radio Mondiale).
a) How do they erase the memory of dinosaur poop from the water molecules in the pills? Dinosaur poop can't be good for me.
Someone thought of that too. "Water memory" doesn't occur unless "activated" by striking the substance with a leather and horsehair-covered paddle.
That could happen if you both enjoy PiÃ±a Coladas and getting caught in the rain.
Agree, so classic!
Be thankful they were just plain laserdiscs - the BBC Domesday Project is an oft-cited example of digital obsolescence, involving weird analogue/digital laserdiscs and custom computer hardware...
If A = B and B = C, then A = C, except where void or prohibited by law. -- Roy Santoro