Method and system for single ended to differential ended demodulation
View Patent ↗Provided are a method and system for demodulating a signal. The method includes receiving the signal along first and second signal paths within a demodulator having a common starting point. Impedance values along each of the paths are changed alternately in synchronism.
1. A method for demodulating a signal, comprising (i) receiving the signal along first and second signal paths within a demodulator, the first and second signal paths having a common starting point and (ii) alternately changing impedance values in a first and a second passive device in a variable fashion within a range of values between a minimum value and a maximum value along each of the paths in synchronism, the alternately changing being in accordance with a shape of a desirable output waveform.
2. The method of claim 1 , wherein the alternately changing is in consonance with one or more demodulation coefficients.
3. A method for demodulating a signal within a demodulator including two or more passive impedance devices, comprising:
receiving the signal as an input to a first of the passive impedance devices, an impedance value of the first passive impedance device (i) being changed from a first impedance value to a relatively small impedance value in a variable fashion and (ii) being changed from the relatively small impedance value to the first impedance value in a variable fashion via one or more intermediate impedance values; and
simultaneously receiving the signal as an input to a second of the passive impedance devices, an impedance value of the second passive impedance device (i) being changed from a relatively small impedance value to a second impedance value in a variable fashion and (ii) being changed from the second impedance value to the relatively small impedance value in a variable fashion via one or more intermediate impedance values;
wherein the impedance values of the first and second passive impedances devices are changed in synchronism, in accordance with a shape of a desirable output waveform.
4. The method of claim 3 , further comprising programming the first impedance value to be substantially equal to the second impedance value.
5. The method of claim 4 , wherein the received signal is modulated at a predetermined modulation frequency; and
wherein the changing occurs at a rate substantially equal to the predetermined modulation frequency.
6. The method of claim 5 , wherein the changing is performed smoothly.
7. The method of claim 5 , wherein the received signal is periodic.
8. The method of claim 7 , wherein a demodulation signal substantially matches the periodic received signal.
9. The method of claim 4 , wherein the received signal is modulated at a predetermined modulation frequency; and
wherein the changing occurs at a rate that exceeds the predetermined modulation frequency.
10. The method of claim 4 , wherein the received signal is modulated using a predetermined pseudo random binary sequence; and
wherein the changing occurs at a rate substantially equal to the predetermined pseudo random binary sequence.
11. The method of claim 10 , wherein the received signal is matched to an independent pseudo random binary sequence.
12. The method of claim 11 , wherein a demodulation signal is matched to the independent pseudo random binary sequence.
13. The method of claim 3 , wherein the impedance values of each of the first and second passive impedance devices is changed based on one or more demodulation coefficients.
14. An apparatus for demodulating a signal in a demodulator including two or more passive impedance devices, comprising:
means for receiving the signal as an input to a first of the passive impedance devices, an impedance value of the first passive impedance device (i) being changed from a first impedance value to a relatively small impedance value in a variable fashion and (ii) being changed from the relatively small impedance value to the first impedance value in a variable fashion via one or more intermediate impedance values; and
means for simultaneously receiving the signal as an input to a second of the passive impedance devices, an impedance value of the second passive impedance device (i) being changed from a relatively small impedance value to a second impedance value in a variable fashion and (ii) being changed from the second impedance value to the relatively small impedance value in a variable fashion via one or more intermediate impedance values;
wherein the impedance values of the first and second passive impedances devices are changed in synchronism, in accordance with a shape of a desirable output waveform.
15. The apparatus of claim 14 , wherein the impedance value of the first and the second passive impedance device is changed based upon one or more demodulation coefficients.
16. The apparatus of claim 15 , wherein said one or more demodulation coefficients are programmable.
17. The apparatus of claim 14 , wherein at least one of the first and the second impedance device includes a resistor ladder.