Say What? My Cross-Talk Problem Is At The Component Level? A Filter, You Say?
The oft-neglected filter takes on renewed significance for system engineers designing RF and microwave products. An industry expert offers tips to avoid interference.
By Anatech Electronics Inc.
The devil is in the details. For system engineers who work for U.S.-based manufacturers of RF and microwave products, that seems to be the message they are painfully discovering. As their products get rushed into the marketplace and put to the test by wireless service providers and consumers, shortcomings in frequency management come home to roost in the form of noise, cross-talk, signal dropouts and even complete transmission interruption. While the product design holds up under scrutiny on paper, test engineers are increasingly rooting out the source of the problem, and oftentimes the solution turns out to be one single component: the filter.
Air Combat
Of course, the difficulty in transmitting and receiving a clear signal stems, in large part, from competition for band space. Just as surely as nature abhors a vacuum, wireless service providers are quickly filling every available frequency gap from UHF frequencies of 300 MHz, all the way up to super high frequencies of 30 GHz and beyond. Even the FCC can't bend the laws of physics, as useful bands quickly fill to capacity, forcing manufacturers to develop devices that operate within tighter and tighter bandwidths.Take the case of cellular phone service providers, who, despite utilizing competing multiplexing protocols, still run into conflict when signal frequencies are adjacent to each other. For instance, the CDMA passband ends at 888.9 MHz, quickly followed by the GSM 900 passband, which begins at 890.1 MHz. With only 1.2 MHz of space between the two, there is little room for error. Harmonics and other spurious signals add to the challenge of maintaining distinct borders between the two.
Click Here To Download:White Paper: Say What? My Cross-Talk Problem Is At The Component Level? A Filter, You Say?