Broadband linearizer with combined second and third order generation with adjustable tilt
Systems and methods can provide an improved broadband linearizer that includes a distortion generator with a bypass path for generating both composite triple beat (CTB) and composite second order (CSO) distortions suitable for linearizing a laser. The linearized laser can be suitable for injection into a communications network such as, for example, a hybrid fiber coaxial (HFC) network, among others.
1. A broadband linearizer system, comprising:
a splitter operable to receive an input signal and to split the input signal into a first signal and a second signal;
a distortion generator operable to receive the second signal and to generate a third signal, the distortion generator comprising:
one or more amplifiers;
one or more non-linear elements; and
wherein the one or more amplifiers and one or more non-linear elements are operable to generate second and third order distortions through adjustable bias currents, and wherein the amplifiers comprise transistors including one or more Schottkey diodes in the emitter feedback path of the amplifiers; and
a combiner operable to combine the first and third signals.
2. The system of claim 1 , wherein the distortion generator comprises a plurality of distortion generator circuits operable to generate frequency dependent amplitude and phase distortions wherein, one or more of the distortion generator circuits is operable to generate adjustable second and third distortion levels.
3. The system of claim 2 , wherein the distortion generator is operable to adjust the relative contributions from the plurality of distortion generator circuits.
4. The system of claim 1 , wherein the distortion generator is operable to spit the second signal into a positive phase signal and a negative phase signal.
5. The system of claim 4 , wherein the positive phase signal is received by one or more distortion generating circuits and the negative phase signal is received by one or more distortion generating circuits wherein, one or more distortion generating circuits are operable to generate second and third order distortions and wherein, the distortion generator is operable to combine the outputs of the one or more distortion generating circuits generating the third output signal.
6. The system of claim 5 , wherein the plurality of distortion generating circuits each having different amplitude and phase dependence on frequency comprise one or more distortion generating circuits operable to generate second and third order distortion levels.
7. The system of claim 1 , wherein the distortion generator includes linear gain adjustment means operable to adjust the linear gain of third order distortions while maintaining a constant gain.
8. The system of claim 1 , wherein one of the one or more amplifiers receives the second signal.
9. The system of claim 8 , wherein further comprising an adjustable attenuator precedes the amplifier.
10. The system of claim 1 , comprising additional in-line distortion generators.
11. A method for providing broadband linearization, comprising:
receiving a input signal;
splitting the input signal into a first and second signal;
generating one or more adjustable second and third order distortion signals from the second signal, wherein one or more amplifiers and one or more non-linear elements are operable to generate second and third order distortions through adjustable bias currents, and wherein the one or more amplifiers comprise transistors having one or more Schottkey diodes in the emitter feedback path of the amplifiers;
generating one or more adjustable frequency dependent amplitude and phase distortion signals from the second signal;
producing a third signal through combining the second and third order distortions signals with the frequency dependent amplitude and phase distortion signals; and
combining the first and third signals.
12. The method of claim 11 , wherein adjustable distortion signals are generated based on non-linear components.
13. The method of claim 11 , wherein the linear gain of the adjustable second are third order distortion signals is controllable.
14. The method of claim 11 , wherein the second signal is signal is split into a positive phase signal and a negative phase signal before generating distortions.
15. The method of claim 11 , wherein one of the one or more amplifiers is operable to receive the second signal prior distortion generation.
16. The method of claim 15 , wherein a variable attenuator is operable to receive the second signal prior to second signal being received by the one or more the amplifiers.
17. A broadband linearizer system, comprising;
input signal;
a splitter operable to split the input signal into a first signal and a second signal;
a distortion generator operable to receive the second signal;
the distortion generator operable with means to generate adjustable frequency independent second and third order distortions, wherein the distortion generator comprises one or more amplifiers and one or more non-linear elements operable to generate second and third order distortions through adjustable bias currents, and wherein the one or more amplifiers comprise transistors having one or more Schottkey diodes in the emitter feedback path of the one or more amplifiers;
the distortion generator further operable with means to generate adjustable frequency dependent amplitude and phase distortions;
the distortion generator further operable to generate a third signal comprising the combined frequency dependent and independent distorted signals; and
a combiner operable to combine the first and third signals.
18. The system of claim 17 , wherein the distortion generator comprises means for generating a positive and negative phase from the second signal.
19. The system of claim 17 , wherein the distortion generator comprises filtering means operable to generate frequency dependent amplitude and phase distortions.