Cross-band broadcasting
A radio communications device has a modulator that modulates each of a number of different carrier signals with the same message. A combiner combines the modulated carrier signals into a single combined output signal. A radio transmitter receives the single combined output signal and in response simultaneously transmits the modulated carrier signals over the air. Other embodiments are also described.
1. A radio communications device, comprising:
a modulator to modulate each of a plurality of different carrier signals with the same message;
a combiner to combine the modulated plurality of carrier signals into a single combined output signal;
a radio transmitter to receive the single combined output signal and in response simultaneously transmit the modulated plurality of carrier signals over the air; and
a peak reduction block coupled between the single combined output signal and the radio transmitter.
2. The device of claim 1 further comprising a digital to analog converter to convert the single combined output signal into analog form,
and wherein the radio transmitter comprises an RF upconverter to receive the analog form of the combined output signal, an RF power amplifier to receive an RF upconverted version of the combined output signal, and an antenna to receive the RF upconverted version of the combined output signal.
3. The device of claim 2 wherein the RF upconverted version of the combined output signal spans the entirety of a communications band in which a plurality of communication channels have been assigned by a government agency except for one or more reserved channels.
4. The device of claim 2 wherein the RF upconverted version of the combined output signal spans a frequency range of 118 MHz to 137 MHz and more than 700 channels in that frequency range.
5. The device of claim 1 wherein the modulator comprises a software-programmed processor that is to produce the modulated plurality of carrier signals as a plurality of digital modulated carrier signals, respectively.
6. The device of claim 1 further comprising:
a carrier generator to produce the plurality of different carrier signals; and
a signal analyzer to receive the combined output signal and to provide a control signal to the carrier generator that adjusts one of phase delay and frequency of one or more of the produced plurality of different carrier signals.
7. The device of claim 1 further comprising:
a signal analyzer to receive the combined output signal and to provide a control signal to the modulator that adjusts one of phase delay, amplitude and time delay of one or more instances of the message.
8. The device of claim 1 further comprising a signal analyzer to receive the combined output signal and to provide a control signal to the peak reduction block.
9. A method for radio communications, comprising:
producing a plurality of different carrier signals each with random starting phase;
modulating each of the plurality of different carrier signals with the same message; and
combining the modulated carrier signals into a single, digital, combined output signal; and
analyzing the digital combined output signal and in response altering the combined output signal to reduce peak levels therein.
10. The method of claim 9 further comprising:
converting the combined output signal into analog form;
frequency upconverting the analog form of the combined output signal; and
transmitting over-the-air the frequency upconverted form of the combined output signal.
11. The method of claim 10 wherein the frequency upconverted form of the combined output signal contains the message in each one of all unreserved communication channels that have been assigned by a government agency to a given RF communications band.
12. The method of claim 9 further comprising
analyzing the combined output signal, and in response adjusting one of a) phase delay and b) frequency of one or more of the plurality of different carrier signals, prior to repeating said modulating operation upon the phase or frequency adjusted one of the carrier signals and then repeating said combining operation.
13. The method of claim 9 further comprising:
analyzing the combined output signal, and in response adjusting one of a) phase delay, b) amplitude, and c) time delay of one or more instances of the message during the modulating operation, prior to repeating said combining operation upon the adjusted one of the modulated carrier signals.
14. The method of claim 9 wherein analyzing the digital combined output signal comprises computing a peak to average ratio of the signal.