4.3.1 Detectors
Diode detectrs provede a measurable low frequency or de voltaje that has a direct and monotonic telationship with the original RF signal's amplitude. Commercial detector blocks are available both as waveguide and as coaxial hardware. They can be used for a variety of tasks.
An example of a leveling arrangement is shown in figure 4.12. When selecting a detector, its frequency range, RF port matching, and speed are the main parameters. Naturally, we are also interested in the sensivity understood here as the conversión coefficient between RF and dc amplitude and in the nature of this unavoidably nonlinear characteristic.
Some applications may require account. The upper end of the dynamic scale can and must normally be adjusted through attenuators, and this is thus not of major concern.
Putting a detector into our system is a relatively straigntforward task. There are two main desing factors to manage. First, although the dynamic range is, in principle, quite large, down to about 60 dBm, one can seldom make use of the lowest values due to noise or interference in the low frequency parts of the system. If other system parameters permit, it might be wisr to desing a detector operation starting form -40 dBm, for example. Second, if we want speed, we lose sensitivity.
Libro: Circuits and Components for System Evaluations and Design
Autor: Pekka Eskelinen
Nombre: Josmar Eduardo Depablos Rodriguez
Asignatura: Circuitos de Alta Frecuencia
Discover the new Windows Vista Learn more!
No hay comentarios:
Publicar un comentario