| 摘要 |
<p>A radio receiver is disclosed for demodulating both wideband and narrowband frequency-modulated signals. The radio receiver improves the capacity of a system by reducing the bandwidth occupancy of analog frequency-modulation systems. The radio receiver comprises a superheterodyne frequency device (40) which converts the received frequency-modulated signal to a fixed intermediate frequency signal. A filter (110) then filters the intermediate frequency signal with a first filter bandwidth adapted to a wideband frequency-modulated signal. The filtered wideband frequency-modulated signal is demodulated in a demodulator using a frequency discriminator (200). The intermediate frequency signal is then filtered using a second and third filter bandwidth (190) adapted to a narrowband frequency-modulated signal. Finally, the further filtered intermediate frequency signal is demodulated using a frequency discriminator (200).</p> |
