Broadband low noise complex regenerative frequency dividers
A regenerative frequency divider device including a plurality of multipliers, each of which has a first input port, a second input port and an output port; a first combiner coupled to the plurality of multipliers so as to receive an output signal from at least two of the multipliers; and a second combiner coupled to the plurality of multipliers so as to receive an output signal from at least two of multipliers. Further, a first output signal generated by the first combiner is coupled to the second input port of at least two of the multipliers; and a second output signal generated by the second combiner is coupled to the second input port of at least two of the multipliers such that a complex signal is fed back to the multipliers performing the down conversion process. The present invention divider CRD can achieve superior output noise floor of −180 dBc/Hz at multi-GHz frequencies.
1. A regenerative frequency divider device performing frequency division by combining signals generated using an external complex input signal with components of the external complex input signal, the regenerative frequency divider device comprising:
a plurality of multipliers, each of which has:
a first input for receiving an external complex input signal having a first frequency, and
a second input for receiving a signal generated using the external complex input signal,
a first combiner coupled to a first multiplier of said plurality of multipliers for receiving an in-phase portion of the external complex input signal, the first combiner coupled to a second multiplier of said plurality of multipliers for receiving a quadrature portion of the external complex input signal, said first combiner outputting an in phase output signal having a frequency fractionally related to the first frequency;
a second combiner coupled to a third multiplier of said plurality of multipliers for receiving an in-phase portion of the external complex input signal, the second combiner coupled to a fourth multiplier of said plurality of multipliers for receiving a quadrature portion of the external complex input signal, said second combiner outputting a quadrature output signal having a frequency fractionally related to the first frequency;
wherein the in phase output signal from the first combiner is couplable to the second input port of at least two of said plurality of multipliers to create a positive closed loop feedback thereof and the quadrature output signal from the second combiner is couplable to the second input port of at least two of said plurality of multipliers to create a positive feedback thereof,
wherein responsive to inputting the in phase and quadrature output signals to the second inputs of the plurality of multipliers, the regenerative frequency divider oscillates synchronously with the external, complex signal received at the first input at the frequency fractionally related to the first frequency.
2. The regenerative frequency divider device of claim 1 , wherein:
an output of the first multiplier is couplable to said first combiner, said first multiplier receiving the in phase portion of the external complex input signal at said first input port and receiving said in phase output signal at said second input;
an output of the second multiplier is couplable to said first combiner, said second multiplier receiving the quadrature portion of the external complex input signal at said first input port and receiving said in phase output signal at said second input;
an output of the third multiplier is couplable to said second combiner, said third multiplier receiving the in phase portion of the external complex input signal at said first input port and receiving said quadrature output signal at said second input; and
an output of the fourth multiplier is couplable to said second combiner, said fourth multiplier receiving the quadrature portion of the external complex input signal at said first input port and receiving said quadrature output signal at said second input.
3. The regenerative frequency divider device of claim 2 , wherein said first combiner operates to sum the output signal from said first multiplier and the output signal from said second multiplier.
4. The regenerative frequency divider device of claim 2 , wherein said second combiner operates to generate a difference signal representing the difference between the output signal of said first multiplier and the output signal of said second multiplier.
5. The regenerative frequency divider device of claim 2 , wherein said quadrature portion of the external complex signal corresponds to a sine portion, and said in phase portion of the external complex signal corresponds to a cosine portion.
6. The regenerative frequency divider device of claim 2 , wherein the combination of outputs from said first and second combiners is a complex output signal having a cosine portion and a sine portion, said in phase output signal of said first combiner corresponding to the cosine portion of said complex output signal and said quadrature output signal of said second combiner corresponding to the sine portion of said complex output signal.
7. A method of performing regenerative frequency division comprising the steps of:
receiving, at a combiner circuit, an external complex input signal, the external complex input signal being an analog signal having a first frequency and having an in-phase component and a quadrature component;
generating, at the combiner circuit, a complex down-converted signal having a second frequency, the second frequency less than the first frequency, by complex mixing said external complex input signal with said complex down-converted signal by feeding-back said complex down-converted signal to a plurality of multipliers performing a down-conversion process,
wherein the regenerative frequency divider, responsive to feeding-back in phase and quadrature components of said complex down-converted signal to the plurality of multipliers, oscillates synchronously with the external complex input signal at a second frequency fractionally related to the first frequency; and
outputting, from the combiner circuit, said complex down-converted signal as an output signal.
8. The method of performing regenerative frequency division of claim 7 , wherein:
an output of a first multiplier of the plurality of multipliers is couplable to a first combiner, said first multiplier receiving an in phase portion of the external complex input signal at said first input port and receiving an in phase output signal from output by the first combiner at said second input;
an output of a second multiplier of the plurality of multipliers is couplable to said first combiner, said second multiplier receiving a quadrature portion of the external complex input signal at said first input port and receiving an in phase output signal output by the first combiner at said second input;
an output of a third multiplier of the plurality of multipliers is couplable to said second combiner, said third multiplier receiving the in phase portion of the external complex input signal at said first input port and receiving said quadrature output signal output by said second combiner at said second input; and
an output of a fourth multiplier of the plurality of multipliers is couplable to said second combiner, said fourth multiplier the quadrature portion of the external complex input signal at said first input port and receiving said quadrature output signal output by said second combiner at said second input.
9. The method of performing regenerative frequency division of claim 8 , wherein said first combiner operates to sum the output signal from said first multiplier and the output signal from said second multiplier.
10. The method of performing regenerative frequency division of claim 8 , wherein said second combiner operates to generate a difference signal representing the difference between the output signal of said first multiplier and the output signal of said second multiplier.
11. The method of performing regenerative frequency division of claim 8 , wherein said quadrature portion of the external complex signal corresponds to a sine portion, and said in phase portion of the external complex signal corresponds to a cosine portion.
12. The method of performing regenerative frequency division of claim 8 , wherein the combination of outputs from said first and second combiners is a complex output signal having a cosine portion and a sine portion, said in phase output signal of said first combiner corresponding to the cosine portion of said complex output signal and said quadrature output signal of said second combiner corresponding to the sine portion of said complex output signal.