Transmitting RF signals employing improved high-level combinations of analog FM and digital signals
View Patent ↗Apparatus and method are presented for broadcasting an RF signal comprised of analog FM and digital signals. An analog FM source provides an analog FM signal. A digital source provides a digital signal. A splitter splits the FM signal into a fractional portion and remainder portion. A summer combines the fractional portion with the digital signal to provide a first combined signal. A main FM transmitter amplifies the remainder portion to provide an amplified FM signal. A digital transmitter amplifies the first combined signal to provide an amplified combined signal. A combiner combines the amplified FM signal and the amplified combined signal to provide a composite RF signal to be broadcasted.
1. An apparatus for broadcasting an RF (radio frequency) signal comprised of analog FM (frequency modulation) and digital signals comprising:
a splitter that receives said analog FM signal for splitting said FM signal into a fractional portion and a remainder portion;
a summer for summing said fractional portion with said digital signal to provide a first combined signal;
a main FM transmitter for amplifying said remainder portion to provide an amplified FM signal;
a digital transmitter for amplifying said first combined signal to provide an amplified combined signal; and
further comprising a combiner that combines said amplified FM signal and said amplified combined signal to provide said RF signal to be broadcasted, a phase adjuster located between said splitter and said summer for adjusting the phase of said fractional portion.
2. An apparatus as set forth in claim 1 wherein said phase adjuster is manually adjusted.
3. An apparatus as set forth in claim 1 wherein said combiner is a signal coupler having a coupling coefficient in the range from about −3 dB to about −9 dB.
4. An apparatus as set forth in claim 3 wherein said adjuster is manually adjusted.
5. An apparatus as set forth in claim 1 wherein said combiner is a signal coupler having a coupling coefficient on the order of around −5 dB.
6. An apparatus as set forth in claim 5 wherein said adjuster is manually adjusted.
7. An apparatus for broadcasting an RF (radio frequency) signal comprised of analog (FM frequency modulation) and digital signals comprising:
a splitter that receives said analog FM signal for splitting said FM signal into a fractional portion and a remainder portion;
a summer for summing said fractional portion with said digital signal to provide a first combined signal;
a main FM transmitter for amplifying said remainder portion to provide an amplified FM signal;
a digital transmitter for amplifying said first combined signal to provide an amplified combined signal; and
said digital signal is an IBOC (inband on channel) digital signal, said apparatus further comprising a combiner that combines said amplified FM signal and said amplified combined signal to provide said RF signal to be broadcasted and including a phase adjuster located between said splitter and said summer for adjusting the phase of said fractional portion.
8. An apparatus as set forth in claim 7 wherein said adjuster is manually adjusted.
9. An apparatus as set forth in claim 7 wherein said combiner is a signal coupler having a coupler coefficient on the order of about −3 dB to about −9 dB.
10. An apparatus as set forth in claim 9 wherein said adjuster is manually adjusted.
11. An apparatus as set forth in claim 7 wherein said combiner is a signal coupler having a coupling coefficient on the order of about −5 dB.
12. An apparatus as set forth in claim 11 wherein said adjuster is manually adjusted.