Logarithmic detector amplifier system for use as high sensitivity selective receiver without frequency conversion

• US 9,590,572 B2
• Filed: 03/17/2014
• Issued: 03/07/2017
• Est. Priority Date: 09/12/2013
• Status: Active Grant

• Current Assignee: DockOn AG
• Original Assignee: DockOn AG
• Inventors: Rada, Patrick Antoine, Brown, Forrest James, Dupuy, Alexandre
• Primary Examiner(s): Urban, Edward
• Assistant Examiner(s): HU, RUI MENG
• Application Number:
  US14/216,945
• Publication Number:
  US 20150070058A1
• Time in Patent Office: 1,086 Days
• Field of Search: 455/254, 455/215, 455334-342
• US Class Current: 1/1
• CPC Class Codes: H03F 1/38 Positive-feedback circuit arrangements without negative feedback
• CPC Class Codes: H03F 1/56 Modifications of input or output impedances, not otherwise provided for
• CPC Class Codes: H03F 2200/129 there being a feedback over the complete amplifier
• CPC Class Codes: H03F 2200/147 the feedback circuit comprising a series resonance circuit
• CPC Class Codes: H03F 2200/222 A circuit being added at the input of an amplifier to adapt the input impedance of the amplifier
• CPC Class Codes: H03F 2200/237 A parallel resonance being added in series in the input circuit, e.g. base, gate, of an amplifier stage
• CPC Class Codes: H03F 2200/241 A parallel resonance being added in shunt in the input circuit, e.g. base, gate, of an amplifier stage
• CPC Class Codes: H03F 2200/243 A series resonance being added in series in the input circuit, e.g. base, gate, of an amplifier stage
• CPC Class Codes: H03F 2200/246 A series resonance being added in shunt in the input circuit, e.g. base, gate, of an amplifier stage, e.g. as a trap
• CPC Class Codes: H03F 2200/261 Amplifier which being suitable for instrumentation applications
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/297 the loading circuit of an amplifying stage comprising a capacitor
• CPC Class Codes: H03F 2200/301 the loading circuit of an amplifying stage comprising a coil
• CPC Class Codes: H03F 2200/306 the loading circuit of an amplifying stage being a parallel resonance circuit
• CPC Class Codes: H03F 2200/309 the loading circuit of an amplifying stage being a series resonance circuit
• CPC Class Codes: H03F 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 2200/391 the output circuit of an amplifying stage comprising an LC-network
• CPC Class Codes: H03F 2200/399 A parallel resonance being added in shunt in the output circuit, e.g. base, gate, of an amplifier stage
• CPC Class Codes: H03F 2200/402 A series resonance being added in shunt in the output circuit, e.g. base, gate, of an amplifier stage
• CPC Class Codes: H03F 2200/438 Separate feedback of amplitude and phase signals being present
• CPC Class Codes: H03F 2200/451 : the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/462 : the current being sensed
• CPC Class Codes: H03F 3/193 : with field-effect devices H03F3/195 takes precedence
• CPC Class Codes: H03F 3/195 : in integrated circuits
• CPC Class Codes: H03F 3/72 : Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal
• CPC Class Codes: H03L 7/06 : using a reference signal applied to a frequency- or phase-locked loop
• CPC Class Codes: H04B 1/22 : for receivers in which no local oscillation is generated

Abstract

A logarithmic detector amplifying (LDA) system is provided for use as a high sensitivity receive booster or replacement for a low noise amplifier in a receive chain of a communication device. The LDA system includes an amplifying circuit configured to receive an input signal having a first frequency and generate an oscillation based on the input signal, a sampling circuit coupled to the amplifying circuit and configured to terminate the oscillation based on a predetermined threshold to periodically clamp and restart the oscillation to generate a series of pulses modulated by the oscillation and by the input signal, and one or more resonant circuits coupled with the amplifying circuit and configured to establish a frequency of operation and to generate an output signal having a second frequency, the second frequency being substantially the same as the first frequency.

Claims

1. A system for use in a receive chain of a communication device, the system comprising:

a logarithmic amplifying circuit configured to receive an input signal at an input of the system having a first frequency and to generate an oscillation based on the input signal;

a sampling circuit coupled to the logarithmic amplifying circuit and configured to;

compare an input signal magnitude of the input signal with a predetermined input signal magnitude threshold; and

terminate the oscillation when the input signal magnitude is equal to or greater than the predetermined input signal magnitude threshold so as to periodically clamp and restart the oscillation to generate a series of voltage spikes;

a first resonant circuit coupled to the logarithmic amplifying circuit and configured to establish a frequency of operation of the system; and

a second resonant circuit coupled to at least one of the first resonant circuit or the logarithmic amplifying circuit and configured to generate an output signal at an output of the system having a second frequency, the second frequency being substantially the same as the first frequency, wherein the output signal is generated without frequency conversion of the input signal.

2. The system of claim 1, wherein:

the second resonant circuit is coupled in series with the logarithmic amplifying circuit at an input side or an output side of the logarithmic amplifying circuit.

3. The system of claim 1, wherein:

the second resonant circuit comprises a series resonant circuit portion coupled in series with the logarithmic amplifying circuit and a parallel resonant circuit portion coupled in parallel with the logarithmic amplifying circuit.

4. The system of claim 3, wherein:

the parallel resonant circuit portion includes an inductor coupled in parallel with two capacitors and a third capacitor coupled to a common node between the two capacitors, wherein values of the inductor and the capacitors are configured to output the signal having the RF frequencies.

5. The system of claim 4, wherein:

the two capacitors and the third capacitor are critically coupled.

6. The system of claim 3, wherein:

the series resonant circuit portion includes a capacitor and an inductor coupled in series.

7. The system of claim 1, wherein:

the second resonant circuit comprises one or more components, the one or more components optimized to match an output impedance.

8. The system of claim 1, wherein:

one or more of the first and second resonant circuits comprise a plurality of components, one or more of which are configured to be of high Q.

9. The system of claim 8, wherein:

the one or more components include one or more of a SAW filter, a BAW filter, a crystal filter, a ceramic filter, a mechanical filter, an LC resonator, an active RC, a variation of RC or LC where C is replaced with a variable capacitor, or an active component with variable capacitance.

10. The system of claim 1, wherein:

the system is configured to replace a low noise amplifier in the receive chain of the communication device.

11. The system of claim 5, wherein:

the second resonant circuit includes at least an inductor, a capacitor, and a resonator.

12. The system of claim 11, wherein:

the inductor is coupled in between the logarithmic amplifying circuit and a voltage source, and wherein the resonator includes one or more of a differential input/output device, a SAW filter, a BAW filter, a crystal filter, a ceramic filter, a mechanical filter, an LC resonator, an active RC, a variation of RC or LC where C is replaced with a variable capacitor, or an active component with variable capacitance.

13. The system of claim 5, wherein:

the second resonant circuit operates independently of the logarithmic amplifying circuit.

14. A system for use as a complement of a low noise amplifier and configured to be placed before or after the low noise amplifier in a receive chain of a communication device, the system comprising:

a logarithmic amplifying circuit configured to receive an input signal at an input of the system having a first frequency and to generate an oscillation based on the input signal;

a sampling circuit coupled to the logarithmic amplifying circuit and configured to;

compare an input signal magnitude of the input signal with a predetermined input signal magnitude threshold; and

terminate the oscillation when the input signal magnitude is equal to or greater than the predetermined input signal magnitude threshold so as to periodically clamp and restart the oscillation to generate a series of voltage spikes;

a first resonant circuit coupled to the logarithmic amplifying circuit and configured to establish a frequency of operation of the system; and

a second resonant circuit coupled to at least one of the first resonant circuit or the logarithmic amplifying circuit and configured to generate an output signal at an output of the system having a second frequency, the second frequency being substantially the same as the first frequency, wherein the output signal is generated without frequency conversion of the input signal, and wherein the input of the system or the output of the system is coupled to the low noise amplifier.

15. The system of claim 14, further comprising:

a phase lock loop having an output split into a first output and a second output, the second output being adapted as an input to a voltage range frequency divider feeding frequency/phase comparator, wherein the comparator is configured to receive a second input signal F_reference frequency divided by a factor M, wherein the comparator output driving a low pass filter through a switch, wherein the switch is enabled by a digitally shaped signal of a second output of the system, and wherein the low pass is driving an additional input of the system.

16. A method for improving receive sensitivity in a receive chain of a communication device, the method comprising:

amplifying, by a logarithmic amplifier, a receive input signal having a first frequency and generating an oscillation based on the input signal;

sampling the amplified signal;

comparing an input signal magnitude of the input signal with a predetermined input signal magnitude threshold;

terminating the oscillation when the input signal magnitude is equal to or greater than the predetermined input signal magnitude threshold so as to periodically clamp and restart the oscillation to generate a series of voltage spikes;

establishing a frequency of operation by a first resonant circuit; and

outputting an output signal having RF frequencies substantially the same as the first frequency by a second resonant circuit without performing frequency conversion of the input signal.

17. The method of claim 16, wherein:

outputting the output signal is performed independently of establishing the frequency of operation.

18. The method of claim 16, wherein:

outputting the output signal includes optimizing the second resonant circuit to match an output impedance.

19. The method of claim 18, further comprising:

increasing a sensitivity of the receive chain by reducing a bandwidth of at least one of the first or the second resonant circuits.

20. The method of claim 19, wherein:

the bandwidth is reduced by at least one of selecting one or more high Q components of at least one of the first or the second resonant circuits, setting an instantaneous logarithmic amplifier gain of the receive chain, or setting a one-cycle-quenching gain of the receive chain.