# gigaherz and telephones

What does it mean when a phone has 2.4 Ghz?? Does it have to do with frequency?? Herz is a speed of the cpu, right??? What are the differences when GHZ is used in CPUs and phones??
Also, Why is it Terraflop as opposed to Terraherz??

It means the frequency it operates on is 2.4 gigahertz, which is 2,400 megahertz. The higher the frequency a cordless phone has, the further it will transmit. For example, a 2.4 gigahertz phone should transmit (from/to it’s base) well over 2 times the distance a 900 megahertz phone will. I own a 2.4 gig phone (Panasonic) and I highly recommend it. I can walk almost a mile away from my estate and still have crystal clear sound. If you get a cordless phone, make sure it says “Digital Spread Spectrum” on it. DSS improves the sound, clarity, and distance of the phone, and it prevents snoops with police scanners from listening in on your conversations.

Mabey it doesn’t Hertz when it flops…

I remember reading something about this. If you don’t mind my laziness, what exactly does DSS do to prevent snooping and do all that other cool stuff?

Hertz (Hz) is a measure of frequency; one Hz = one cycle per second. When talking about cordless phones, the Hz the manufacturer is measuring is the frequency of the radio wave that the cordless phone uses to communicate with the base unit; the radio wave oscillates in the 2.4GHz (2.4 billion cycles per second) range. The radio wave doesn’t oscillate at exactly 2.4GHz; it operates on a frequency within a range that is centered around ~2.4GHz.

Hz in a processor is the number of computing cycles that a processor can run through each second. In one computing cycle, a processor can do any number of different things: multiply two numbers, move data from one memory location to another, etc… The type and number of operations than can be accomplished in one processor cycle are dependent upon the design of the processor.

Flops is a floating-point operation per second. A floating-point operation is a mathematical operation (add, multiply, etc…) that involves fractional numbers. So a processor that has a peak processing output of one terraflops can perform one trillion floating-point operations each second. A processor than runs at one terrahertz is running through one trillion processor cycles every second, with any number of operations occuring each processor cycle (floating point operations, integer operations, or whatever the processor was designed to accomplish).

Since it doesn’t stay at one frequency for more than a few tens of milliseconds (0.010 seconds,) you won’t find a scanner capable of keeping up. Also, the audio is transmitted digitally and coded. That means that you don’t hear static in the received audio, and it also means that even if you had a fast enough scanner, all you would hear would be a god awful racket from the digital signal.

Yes, the phone operates in a frequency range around 2,400 Megahertz.
No, the higher frequency does not automatically equate to greater transmit range.
DSS means that the transmit frequency is changed randomly while you are using the phone. The “randomly changes” part is the “Spread Spectrum.” The “Digital” part refers to the fact that the frequency changes are controlled by the microprocessors in the base unit and in the handset.
Digital telephones may well be allowed to use higher transmit power than the old 900 MHz analog phones. Multiple digital phones in the same band can operate close together with no interference, and no one hearing part of someone else’s conversation.

Not automatically no, but in practice it usually does. most 2.4 gig phones transmit longer than a 900 megahertz phone, and all 900 and 2.4 phones transmit longer than the old 46/49 megahertz phones. Another thing I forgot: Not all 2.4 gig phones are digital spread spectrum. Panasonic had one that wasn’t, and quite a few consumers got angry that their phones could be picked up on scanners. Also, digital and digital spread spectrum are not exactly the same things, though both are secure.

In actual fact, a higher frequency signal will have lower range than a lower frequency signal if the transmit power and receiver sensitivity are the same. The lower frequency bands have lower transmit power restrictions imposed on them by the FCC. Along with this goes the fact that the antennas used in the lower frequency ranges (46/49 MHz)are actually too short. There is a direct relationship between frequency and antenna length such that for a 46MHz phone, you would need antennas of five feet and 4 inches length on the base station and the phone. Maybe you could live with the long antenna on the base, but the one on the phone would be a real nuisance. For the 900 MHz phones, you only need a three inch antenna and the 2.4GHz phones only need an antenna 1.3 inches long. So, you see, the higher frequency phones can have proper antennas that aren’t inconveniently long. This gives them better range from the start, and when you add in the facts that you are allowed to use more transmit power in the higher frequencies and that the higher frequency phones are built with newer, better performing receivers, then the higher frequency phones have better range than the lower frequency ones. The better range, however, is not caused by the higher frequency.

Just to clarify: Speed in a processor is a measure of the speed of the CLOCK in the processor. Gates in a processor operate on clock ticks - which can best be approximated by a square wave that runs at the processor frequency. It basically goes from a high voltage to a low voltage rapidly. Some gates/flip flops are designed to operate on the high edge of the clock, some on the low, and some on both.

Jman