The impedance adaptation is important in two situations. The first occurs at low power when the received signal at the input of an amplifier is very low and next-level electrical noise of the amplifier. Motorola If the transfer is not optimal signal, the signal to noise ratio worse. We find this situation, for example, the low radio signal reception. Interestingly, the cable that connects the antenna to the receiver at the two ends adapted to maximize the power transferred from the antenna to the cable and then the cable to the receiver.
Another situation in which the impedance adaptation is important occurs in high frequency systems. For example, in a transmitter operating at microwave frequencies, which consists (among others) by a generator, a waveguide and an candy bar phone antenna. If the waveguide and the antenna is not suitable, a part of the incident power is reflected at the antenna and create a wave in the guide. If the mismatch is significant, and the transmitted power is high enough, cell phones the source can be damaged by the reflected wave. In plans practice additional protections are used between the source and the waveguide, so that reflected signals from loading are attenuated.
You should not think that in all situations, the ideal is that the impedances of you get a free cell phone when you join any of the plans the source and load wireless providers are adapted. In many cases, adaptation is harmful slider phone and should be avoided. The reason is that, as explained earlier, when there is adaptation, the power dissipated in the load is equal to the power dissipated in the resistance of the impedance of the source. The adjustment corresponds to a maximum energy yield of 50 . If you Nokia want a good performance requires that the resistance of the source is negligible with respect to the resistance of the load. An example is the production and distribution of electricity by the electricity companies. get your cellular plan together with free cell phones If the generating companies were adapted to the grid, half the power generated all the plans include free cell phones by the companies only serve to heat generators ... and melt. Also, if your desk lamp was adapted cell phones to the network, consuming half the power generated by the electricity company.
Take another example less caricature: a radio transmitter connected to cellular phones the antenna via a cable. If cellular coverage the cellular phones adjustment of Free cell phones the cable to LG the antenna is desirable (not to be reflected waves), it is wireless phones best to avoid adapting the cable to the transmitter. If the issuer was adapted, half the power generated by the issuer would be lost Samsung in the internal resistance of the latter. The best thing is that the issuer's internal resistance as small as possible.
There are other HTC cases in which adaptation is cellular providers simply impossible. For example, the internal resistance mobile phones of a car antenna on medium wave and long wave is very small (a few milliohms). Unable to adapt or cable or antenna to the receiver. But cellular phone plans that does not prevent the operation of free phones the auto-radios.
Another case in which the current adjustment of the antenna to the receiver and the sender is impossible is that of mobile phones. As the impedance of the antenna depends on the position of the head and the hand of the user, adapting to all circumstances is impossible. But that does not prevent free cell phones with every plan them from working.