Advanced Designs
To overcome obstacles such as image response, multiple IF stages are used, and in some cases multiple stages with two IFs of different values are used. For example, the front end might be sensitive to 1–30 MHz, the first half of the radio to 5 MHz, and the last half to 50 kHz. Two frequency converters would be used, and the radio would be a double conversion superheterodyne; a common example is a television receiver where the audio information is obtained from a second stage of intermediate-frequency conversion. Receivers which are tunable over a wide bandwidth (e.g. scanners) may use an intermediate frequency higher than the signal to improve image rejection.
Read more about this topic: Superheterodyne Receiver
Famous quotes containing the words advanced and/or designs:
“In the United States all business not transacted over the telephone is accomplished in conjunction with alcohol or food, often under conditions of advanced intoxication. This is a fact of the utmost importance for the visitor of limited funds ... for it means that the most expensive restaurants are, with rare exceptions, the worst.”
—John Kenneth Galbraith (b. 1908)
“He began therefore to invest the fortress of my heart by a circumvallation of distant bows and respectful looks; he then entrenched his forces in the deep caution of never uttering an unguarded word or syllable. His designs being yet covered, he played off from several quarters a large battery of compliments. But here he found a repulse from the enemy by an absolute rejection of such fulsome praise, and this forced him back again close into his former trenches.”
—Sarah Fielding (1710–1768)