Method for synchronization of received signals

An apparatus for attaining synchronization in a digital transmission system, comprising:

• a controller programmable to perform the steps of:
• determining a signal envelope for a received digital signal, the received digital signal carrying transmitted data and a guard period during which no signal is transmitted;
• filtering the signal envelope using a matched filter having a span corresponding to the guard period;
• and
• determining the guard period from the filtered signal envelope to provide a time reference for the received digital signal;
• wherein said step of determining the guard period includes determining the minimum level of the filtered signal envelope to indicate the center of the guard period.

A digital transmission system, comprising:

• a transmitter for transmitting a digital signal carrying user data using an RF carrier;
• a receiver to receive the digital signal including:
• a controller programmable to perform the steps of:
• determining a signal envelope for a received digital signal, the received digital signal carrying transmitted data and a guard period during which no signal is transmitted;
• determining a signal envelope for the received digital signal;
• filtering the signal envelope using a matched filter matched to the guard period;
• and
• determining the guard period from the filtered signal envelope to provide a time reference for the received digital signal;
• wherein said step of determining the guard period includes determining the minimum level of the filtered signal envelope to indicate the center of the guard period.