Abstract: In a video conferencing system including stations at a plurality of different sites, and in which system first and second video channels are simultaneously displayed at each site station on a picture-in-picture video monitor, a site controller causes a video decoder at the site to decode either a video signal generated at the site or a video signal received from another site via the first video channel. The site controller also responds to a channel assignment signal generated by a system controller by assigning the first video channel to either a first predetermined broadcast frequency or to a second predetermined broadcast frequency and by assigning a second video channel carrying a video signal received from another site to the other of the first and second predetermined broadcast frequencies.

Abstract: A signal acquisition system rapidly acquires carrier phase and symbol timing of a received PSK-modulated communication signal having a 110-symbol pattern through joint estimation of carrier-phase adjustment and symbol-timing adjustment by processing a common set of sampled data. A reference signal at a local oscillator frequency is mixed with a received communication signal to provide the communication signal at an intermediate frequency. The intermediate-frequency communication signal is converted into a digital communication signal, which is formatted into in-phase (I) and quadrature-phase (Q) components.