Method to inject hierarchical data onto single carrier stream
The present invention involves a transmitter for transmitting two levels of data in a hierarchical transmission system. The transmitter has encoders, a modulator, an adjuster, and an up converter. The first encoder has a first output and capable of providing digital information based on a first level of data on the first output. The second encoder has a second output and is capable of providing digital information based on a second level of data on the second output. The modulator is coupled to the first encoder and has I and Q outputs. The adjuster is coupled to the modulator and second encoder and modifies signals on the I and Q outputs of the modulator to produce transmission I and transmission Q outputs. The up converter is coupled to the adjuster and is capable of transmitting broadcast radio signals based on the transmission I and transmission Q outputs. The modulator may include a root raised cosine filter and/or a QPSK modulator. The I and Q outputs of the modulator include analog I and analog Q signals. The adjuster includes an inverter, a phase rotator circuit, a combiner, and/or a limiter. The transmission I and transmission Q outputs of the adjuster include analog I and analog Q signals.
1. A transmitter for transmitting two levels of data in a hierarchical transmission system comprising:
a first encoder having a first output and capable of providing digital information based on a first level of data on said first output;
a second encoder having a second output and capable of providing digital information based on a second level of data on said second output;
a modulator coupled to said first encoder and having I and Q outputs;
an adjuster coupled to said modulator and said second encoder and modifying signals on said I and Q outputs of said modulator, said adjuster having transmission I and transmission Q outputs; and
an up converter coupled to said adjuster and capable of transmitting broadcast radio signals based on said transmission I and transmission Q outputs.
2. The transmitter of claim 1 wherein said modulator includes a root raised cosine filter.
3. The transmitter of claim 1 wherein said modulator includes a QPSK modulator.
4. The transmitter of claim 1 wherein said I and Q outputs of said modulator include analog I and analog Q signals.
5. The transmitter of claim 1 wherein said adjuster includes a root raised cosine filter coupled to at least one of said first and second outputs.
6. The transmitter of claim 1 further comprising a limiter coupling said I and Q outputs of said modulator to said adjuster.
7. The transmitter of claim 1 wherein said transmission I and transmission Q outputs of said adjuster include analog I and analog Q signals.