| 摘要 |
<p>The signal is picked-up by the antenna (1), amplified at (2), mixed at (4) with the signal generated in the local voltage-controlled oscillator (17), amplified at the intermediary frequency stage (5), supplied to the detector (6) and amplified at (7) to supply the loud-speakers (8). Only certain predetermined values can be introduced in the divider (13) of the PLL loop and, as a result the receiver can only be tuned to certain frequencies comprised in each band. Such device is appropriate to set up a communication channel defined between one or a plurality of radio broadcasting stations/channels, and is therefore capable of increasing and customizing the audience of such radio stations. Various alternatives are considered; analog or digital tuning; by direct set up of the frequency or by scanning and comparison; use of the RDS/RBDS systems; operation in frequency bands of analog radio broadcasting (modulation of amplitude and modulation of frequency) and of digital radio broadcasting (DAB Eureka-147/IBOC/IBAC). <IMAGE></p> |
