Method and apparatus for high fidelity wireless stereophonic transmission utilizing dual frequency carriers
View Patent ↗A method and system is disclosed for transmitting two related channels of signals through the air. A first channel of signals is modulated with a first carrier frequency, and a second channel of signals is modulated with a second carrier frequency. The modulated first channel of signals and the second channel of signals are then combined through a high isolation combiner. Thereafter, the combined signals are transmitted toward a receiver system. After receiving the transmitted signals, the first channel and the second channel of signals are regenerated in the receiver system by separating one from the other.
1. A method for transmitting two related channels of signals through the air, the method comprising:
modulating a first channel of signals with a first carrier frequency;
amplifying the first carrier frequency modulated with the first channel of signals;
modulating a second channel of signals with a second carrier frequency;
amplifying the second carrier frequency modulated with the second channel of signals;
combining the amplified and modulated first channel of signals and the second channel of signals through a high isolation combiner, which provides a high degree of isolation therebetween;
coupling the combined signals from the high isolation combiner directly to a single antenna output;
transmitting the combined signals to a receiver system; and
regenerating the first channel and the second channel of signals in the receiver system by separating one from the other.
2. A dual carrier wireless transmitter apparatus, comprising:
a first voltage controlled oscillator, having a first base band signal coupled to deviate a first oscillator frequency, thereby outputting a first modulated carrier signal;
a second voltage controlled oscillator, having a second base band signal coupled to deviate a second oscillator frequency, thereby outputting a second modulated carrier signal;
a high isolation combiner coupled to combine said first modulated carrier signal and said second modulated carrier signal directly to a single antenna output, and operable to provide a high degree of isolation therebetween;
a first amplifier coupled to amplify said first modulated carrier signal before input to said high isolation combiner, and
a second amplifier coupled to amplify said second modulated carrier signal before input to said high isolation combiner.
3. The apparatus of claim 2 wherein said first voltage controlled oscillator further comprises a dielectric resonator oscillator.
4. The apparatus of claim 2 wherein said first base band signal comprises analog audio signals.
5. The apparatus of claim 4 wherein said analog audio signals comprise frequency components in the range of 50 Hz to 20 kHz.
6. A dual carrier wireless transmitter apparatus, comprising:
a first voltage controlled oscillator, having a first base band signal coupled to deviate a first oscillator frequency, thereby outputting a first modulated carrier signal, wherein said first base band signal deviates said first oscillator frequency by about 150 kilohertz;
a second voltage controlled oscillator, having a second base band signal coupled to deviate a second oscillator frequency, thereby outputting a second modulated carrier signal, and
a high isolation combiner coupled to combine said first modulated carrier signal and said second modulated carrier signal to directly a single antenna output, and operable to provide a high degree of isolation therebetween.
7. A wireless receiver apparatus for demodulating a radio frequency signal, having a first modtdated carrier signal and a second modulated carrier signal, into a first base band signal and a second base band signal, comprising:
a first mixer coupled to down-convert the radio frequency signal to a first intermediate frequency signal;
a first filter coupled to filter said first intermediate frequency signal, said first filter having a pass band of sufficient width to pass both of the down-convened first and second modulated carrier signals;
a second mixer coupled to down-convert said filtered first intermediate frequency signal to a second intermediate frequency signal;
a second filter coupled to filter said second intermediate frequency signal, said second filter having a pass band of such center frequency and width as to pass only the down-converted first modulated carrier signal, and
a third filter coupled to filter said second intermediate frequency signal, and having a pass band of such center frequency and width as to pass only the down-converted second modulated carrier signal.
8. The apparatus of claim 7 further comprising:
a first demodulator coupled to demodulate the filtered and down-converted first modulated carrier signal, and
a second demodulator coupled to demodulate the filtered and down-converted second modulated carrier signal.
9. The apparatus of claim 7 wherein said first mixer is coupled to a first local oscillator.
10. The apparatus of claim 7 wherein said second mixer is coupled to a second local oscillator.
11. The apparatus of claim 7 wherein said second filter has a pass band of sufficient width to pass a frequency modulated signal that is deviated about 150 kilohertz.
12. The apparatus of claim 7 wherein the first base band signal comprises analog audio signals.
13. The apparatus of claim 12 wherein the analog audio signals comprise frequency components in the range of 50 Hz to 20 kHz.
14. A method of receiving and demodulating a radio frequency signal, having a first modulated carrier signal and a second modulated carrier signal, into a first base band signal and a second base band signal, comprising the steps of:
down-converting the radio frequency signal to a first intermediate frequency signal;
filtering said first intermediate frequency signal through a pass band of sufficient width to pass both or the down-converted first and second modulated carrier signals;
down-converting said filtered first intermediate frequency signal to a second intermediate frequency signal;
filtering said second intermediate frequency signal through a pass band of such center frequency and width as to pass only the down-converted first modulated carrier signal, and demodulating the first base band signal therefrom, and
filtering said second intermediate frequency signal through a pass band of such center frequency and width as to pass only the down-converted second modulated carrier signal, and demodulating the second base band signal therefrom.
15. The method of claim 14 wherein said filtering said second intermediate frequency signal steps employ a pass band of sufficient width to pass a frequency modulated signal that is deviated about 150 kilohertz.
16. The method of claim 14 wherein the first base band signal comprises analog audio signals.
17. The method of claim 16 wherein the analog audio signals comprise frequency components in the range of 50 Hz to 20 kHz.