Abstract:
In a method for transmitting a data stream in a digital transmission system, the data stream is transmitted in a transmitted signal using successive OFDM symbols; a number of OFDM symbols are combined in a transmission frame; a number of transmission frames are transmitted in one transmission superframe; each transmission superframe has an information block having one or more OFDM symbols in an established position of the transmission superframe; a first transmitted signal having a first data stream in a first carrier frequency range and a second transmitted signal having a second data stream having the same information content as the first data stream are transmitted in a second carrier frequency range; and the time duration of the transmission superframes of the first transmitted signal is an integer multiple of the time duration of the transmission superframes of the second transmitted signal.
Abstract:
An AM simulcast broadcast signal combining a digital transmission signal and an analogue transmission signal in one transmission channel. The digital transmission signal is modulated to one sideband of a carrier of the transmission channel and a correcting signal (C) is modulated to the other sideband of the carrier of the transmission channel, which correcting signal (C) is determined so that the envelope demodulation of the transmission channel represents the analogue transmission signal.
Abstract:
A method for detecting the digital quality of a radio signal includes: receiving a radio signal including a digital portion modulated by a series of symbols each including a plurality of samples; computing correlation points between endpoint samples in cyclic prefix regions of adjacent symbols; and using the correlation points to produce a digital signal quality metric. Receivers that implement the method are also provided.