| 摘要 |
<p>A technique for transmitting wideband signals such as video signals over a communication system such as a cellular or Personal Communication System (PCS) which only has narrowband channels. The video signal is first digitalized and compressed, and then forwarded to a commutating switch, together with any other narrowband signals which are to be transmitted using the same system. The commutating switch demultiplexes the video signal into multiple digital channel signals. The number of digital channel signals dedicated to carrying the video signals may vary as a system controller determines the availability of channel space in the system. The output channels from the switch are then each modulated as required by the particular wireless communication system in use, and forwarded to a digital combiner to produce a wideband composite signal. At a receiving site, the process is reversed, and a digital filter bank, or channelizer, separates the digital channel signals and forwards them to a set of digital demodulators. The demodulated signals are then fed to a multiplexing switch, which, under command from a controller which receives instructions from a system channel assignment controller, directed the channel signals containing the video information to a first-in first-out buffer memory. The reconstructed digital video signal is then decompressed and converted back to analog form for display.</p> |
