Hybrid linear and polar modulation apparatus
The invention is directed at a hybrid modulation apparatus which combines a polar modulation circuit and a linear modulation circuit. The hybrid apparatus allows a communications device to function as a polar or a linear modulation circuit with less components as the output of the linear modulation circuit is an input of the polar modulation circuit.
1. A hybrid linear and polar modulation apparatus comprising:
a linear modulation circuit; and
a polar modulation circuit including only an amplifier for receiving a digital polar modulation input and the linear modulation output;
whereby an input of the polar modulation circuit is an output of the linear modulation circuit.
2. The hybrid linear and polar modulation apparatus of claim 1 wherein the linear modulation circuit comprises:
a first multiplier for multiplying a first input with a predetermined first value to produce a first product;
a second multiplier for multiplying a second input with a predetermined second value to produce a second product; and
a summer for adding the first product to the second product to produce the linear modulation output.
3. The hybrid linear and polar modulation apparatus of claim 2 wherein the polar modulation circuit comprises:
an amplifier for receiving a polar modulation input and the linear modulation output.
4. The hybrid linear and polar modulation apparatus of claim 1 further comprising:
a signal converter, connected to inputs of the linear modulation circuit and the polar modulation circuit, for converting data to linear or polar values.
5. The hybrid linear and polar modulation apparatus of claim 4 further comprising:
a set of digital to analog converters located between the signal converter and the inputs.
6. The hybrid linear and polar modulation apparatus of claim 1 wherein an output of the polar modulation circuit is to an antenna for transmitting the output.
7. The hybrid linear and polar modulation apparatus of claim 4 wherein the signal converter converts the data to polar equivalents.
8. The hybrid linear and polar modulation apparatus of claim 4 wherein the signal converter converts the data to linear equivalents.
9. The hybrid linear and polar modulation apparatus of claim 7 wherein the polar equivalents are R(t), sin θ(t) and cos θ(t).
10. The hybrid linear and polar modulation apparatus of claim 1 wherein the polar modulation input is R(t).
11. The hybrid linear and polar modulation apparatus of claim 2 wherein:
the first input is sin θ(t) and the first predetermined value is cos ωt.
12. The hybrid linear and polar modulation apparatus of claim 2 wherein:
the second input is cos θ(t) and the second predetermined value is sin ωt.