![]() ![]() In most cases, such as integrated circuits, properly made and tuned antennas, TV and radio receivers, transmitters, etc. In this case, it is best to use a PI filter or L filter calculator. When designing LC filters, we will talk about source resistance and load resistance instead of impedance, because if the load or source has some series or parallel inductance or capacitance, and therefore non-resistive impedance the calculations get much more complex. We will cover low-pass LC filters because radio power amplifiers only generate harmonics, and harmonic signals are always the whole multiple of the base signals, so they always have higher frequencies than the base signal – this is why we use low-pass filters, they let the wanted signal through while getting rid of harmonics. Filtering is especially important on the output of power RF amplifiers because they generate a lot of unwanted harmonics that have to be filtered before they are transmitted by the antenna because they can cause interference and transmitting on frequencies other than the ones the station is approved to transmit on can be illegal. ![]() Various LC filters can be used to match impedances and provide filtering. There are many types of filter circuits that can be used in for Impedance matching, the most common ones are discussed in this article. ![]() Apart from using an impedance matching transformer, designers can also use Impedance Filter circuits at the output of an RF amplifier which can double up as a filtering circuit and also as an impedance matching circuit. In the previous article, we discussed the basics of impedance matching and how to use an impedance matching transformer. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |