Satellite payload processing system for switching uplink signals to time division multiplexed downlink signals

Apparatus for switching symbols in parallel broadcast channels transmitted as respective frequency division multiple access carriers to time division multiplexed data streams comprising:

• first and second ping-pong buffers, said first ping-pong buffer being configured to store a first plurality of said symbols in said parallel broadcast channels therein, said second ping-pong buffer being operable to store a second plurality of said symbols in said parallel broadcast channels therein, said second plurality of said symbols in said parallel broadcast channels having arrived at said second ping-pong buffer prior to the arrival of said first plurality of said symbols in said parallel broadcast channels at said first ping-pong buffer;
• a routing switch connected to the outputs of said first and second ping-pong buffers;
• and
• a first frame assembler connected to said routing switch, said routing switch being operable to control the writing of the contents of said second ping-pong buffer to said first frame assembler.