Simultaneous accommodation of a low power signal and an interfering signal in a radio frequency (RF) receiver

• US 9,509,351 B2
• Filed: 07/27/2012
• Issued: 11/29/2016
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Original Assignee: Tahoe RF Semiconductor, Inc. (Renesas Electronics Corporation)
• Inventors: Kennedy, Jonathan Lee, Shaw, Michael Joseph, Livezey, Darrell Lee, Laskar, Joy
• Primary Examiner(s): Maung, Nay A
• Assistant Examiner(s): PEREZ, ANGELICA
• Application Number:
  US13/559,745
• Publication Number:
  US 20140030981A1
• Time in Patent Office: 1,586 Days
• Field of Search: 455/631, 455/296, 455/234.1, 455/63.1, 455/130
• US Class Current: 1/1
• CPC Class Codes: H03L 7/06 using a reference signal applied to a frequency- or phase-locked loop
• CPC Class Codes: H04B 1/0028 wherein the AD/DA conversion occurs at baseband stage
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes

Abstract

A method includes providing a highly linear front end in a Radio Frequency (RF) receiver, implementing a high Effective Number of Bits (ENOB) Analog to Digital Converter (ADC) circuit in the RF receiver, and sampling, through the high ENOB ADC circuit, at a frequency having harmonics that do not coincide with a desired signal component of an input signal of the RF receiver to eliminate spurs within a data bandwidth of the RF receiver. The input signal includes the desired signal component and an interference signal component. The interference signal component has a higher power level than the desired signal component. The method also includes simultaneously accommodating the desired signal component and the interference signal component in the RF receiver based on an increased dynamic range of the RF receiver and the high ENOB ADC circuit provided through the highly linear front end and the high ENOB ADC circuit.

Claims

1. A method comprising:

providing a highly linear front end in a Radio Frequency (RF) receiver;

wherein the RF receiver is at least one of a high band channel receiver and a low band channel receiver;

wherein the high band channel receiver is configured to receive a Global Positioning System (GPS) carrier signal L₁ carrying a standard positioning code along with navigational data, and the low band channel receiver is configured to receive a GPS carrier signal L₂ carrying a precision positioning code, each of the high band channel receiver and the low band channel receiver being capable of receiving L₁ and L₂ respectively with precision and mitigating ionospheric effects from L₁ and L₂ respectively, L₁ having a higher frequency than L₂;

implementing a 12 Effective Number of Bits (ENOB) Analog to Digital Converter (ADC) circuit in the RF receiver along with the provided highly linear front end to enable the RF receiver have a dynamic range of at least 60 dB;

sampling, through the 12 ENOB ADC circuit, at a frequency having harmonics that do not coincide with a desired signal component of an input signal of the RF receiver to eliminate spurs within a data bandwidth of the RF receiver, the input signal including the desired signal component and an interference signal component, and the interference signal component having a power level at least 60 dB higher than that of the desired signal component;

simultaneously accommodating the desired signal component and the interference signal component in the RF receiver based on the at least 60 dB dynamic range of the RF receiver and the 12 ENOB ADC circuit provided through the highly linear front end and the 12 ENOB ADC circuit; and

placing the interference signal component at an image frequency location of an image reject mixer at an IF stage of the RF receiver to reduce a power level of the simultaneously accommodated interference signal component.

2. The method of claim 1,

wherein the RF receiver includes an RF mixer and the image reject mixer in a double superheterodyne configuration thereof, and

wherein the method further comprises providing a clock signal to the 12 ENOB ADC circuit divided down in frequency from an output of a Voltage Controlled Oscillator (VCO) providing a local oscillator reference signal to the image reject mixer to reduce a jitter thereof.

3. The method of claim 2, further comprising at least one of:

controlling a gain of at least one of a Variable Gain Amplifier (VGA) utilized to amplify an output of the RF mixer and a VGA utilized to amplify an output of the image reject mixer through an Automatic Gain Control (AGC) circuit provided in a feedback path of the image reject mixer.

4. The method of claim 1, comprising implementing a Hartley architecture of the image reject mixer.

5. A method comprising:

providing an RF receiver having a dynamic range of at least 60 dB to simultaneously accommodate a desired signal component of an input signal and an interference signal component thereof, the interference signal component having a power level at least 60 dB higher than that of the desired signal component, the RF receiver having a double superheterodyne configuration comprising an RF mixer and an image reject mixer, and the provision of the RF receiver having the dynamic range of at least 60 dB further comprising;

providing a highly linear front end in the RF receiver,

implementing a 12 ENOB ADC circuit in the RF receiver, and

sampling, through the 12 ENOB ADC circuit, at a frequency having harmonics that do not coincide with the desired signal component to eliminate spurs within a data bandwidth of the RF receiver; and

selecting an image frequency of the image reject mixer to coincide with a frequency of the interference signal component to enable cancelation thereof through the image reject mixer while having a capability to receive the desired signal component;

wherein the RF receiver is at least one of a high band channel receiver and a low band channel receiver;

wherein the high band channel receiver is configured to receive a Global Positioning System (GPS) carrier signal L₁ carrying a standard positioning code along with navigational data and the low band channel receiver is configured to receive a GPS carrier signal L₂ carrying a precision positioning code, each of the high band channel receiver and the low band channel receiver being capable of receiving L₁ and L₂ respectively with precision and mitigating ionospheric effects from L₁ and L₂ respectively, L₁ having a higher frequency than L₂.

6. The method of claim 5, further comprising providing a clock signal to the 12 ENOB ADC circuit divided down in frequency from an output of a VCO providing a local oscillator reference signal to the image reject mixer to reduce a jitter thereof.

7. The method of claim 5, further comprising at least one of:

controlling a gain of at least one of a VGA utilized to amplify an output of the RF mixer and a VGA utilized to amplify an output of the image reject mixer through an AGC circuit provided in a feedback path of the image reject mixer.

8. The method of claim 5, comprising implementing a Hartley architecture of the image reject mixer.

9. A method comprising:

implementing a 12 ENOB ADC circuit in an RF receiver having a double superheterodyne configuration comprising an RF mixer and an image reject mixer;

wherein the RF receiver is at least one of a high band channel receiver and a low band channel receiver;

wherein the high band channel receiver is configured to receive a Global Positioning System (GPS) carrier signal L₁ carrying a standard positioning code along with navigational data and the low band channel receiver is configured to receive a GPS carrier signal L₂ carrying a precision positioning code, each of the high band channel receiver and the low band channel receiver being capable of receiving L₁ and L₂ respectively with precision and mitigating ionospheric effects from L₁ and L₂ respectively, L₁ having a higher frequency than L₂;

utilizing an output of a VCO to generate a local oscillator reference signal to the image reject mixer;

providing a clock signal to the 12 ENOB ADC circuit divided down in frequency from the output of the VCO providing the local oscillator reference signal to the image reject mixer to reduce a jitter thereof;

providing a highly linear front end in the RF receiver along with the 12 ENOB ADC circuit to enable the RF receiver have a dynamic range of at least 60 dB;

sampling, through the 12 ENOB ADC circuit, at a frequency having harmonics that do not coincide with a desired signal component of an input signal of the RF receiver to eliminate spurs within a data bandwidth of the RF receiver, the input signal including the desired signal component and an interference signal component, and the interference signal component having a power level at least 60 dB higher than that of the desired signal component;

simultaneously accommodating the desired signal component and the interference signal component in the RF receiver based on the at least 60 dB dynamic range of the RF receiver and the 12 ENOB ADC circuit provided through the highly linear front end and the 12 ENOB ADC circuit; and

placing the interference signal component at an image frequency location of the image reject mixer at an IF stage the RF receiver to reduce a power level of the simultaneously accommodated interference signal component.

10. An integrated circuit (IC) chip comprising:

a high band channel receiver configured to receive a Global Positioning System (GPS) carrier signal L₁ carrying a standard positioning code along with navigational data; and

a low band channel receiver configured to receive a GPS carrier signal L₂ carrying a precision positioning code, each of the high band channel receiver and the low band channel receiver being capable of receiving L₁ and L₂ respectively with precision and mitigating ionospheric effects from L₁ and L₂ respectively, L₁ having a higher frequency than L₂, and the each of the high band channel receiver and the low band channel receiver comprising;

a highly linear front end; and

a 12 ENOB ADC circuit along with the highly linear front end to enable the each of the high band channel receiver and the low band channel receiver have a dynamic range of at least 60 dB, a sampling frequency of the 12 ENOB ADC circuit having harmonics that do not coincide with a desired signal component of each of L₁ and L₂ to eliminate spurs within a data bandwidth of the each of the high band channel receiver and the low band channel receiver, the each of L₁ and L₂ additionally including an interference signal component having a power level at least 60 dB higher than that of the desired signal component,

wherein the each of the high band channel receiver and the low band channel receiver is configured to simultaneously accommodate the desired signal component and the interference signal component of the each of L₁ and L₂ based on the at least 60 dB dynamic range of the each of the high band channel receiver and the low band channel receiver and the 12 ENOB ADC circuit provided through the highly linear front end and the 12 ENOB ADC circuit, and

wherein the each of the high band channel receiver and the low band channel receiver comprises an image reject mixer at an IF stage thereof at whose image frequency location the simultaneously accommodated interference signal component is placed to reduce a power level thereof.

11. The IC chip of claim 10,

wherein the each of the high band channel receiver and the low band channel receiver includes an RF mixer and the image reject mixer in a double superheterodyne configuration thereof.

12. The IC chip of claim 10, wherein the image reject mixer is based on a Hartley architecture.

13. An in-band cancellation system comprising:

an RF receiver;

wherein the RF receiver is at least one of a high band channel receiver and a low band channel receiver;

wherein the high band channel receiver is configured to receive a Global Positioning System (GPS) carrier signal L₁ carrying a standard positioning code along with navigational data, and the low band channel receiver configured to receive a GPS carrier signal L₂ carrying a precision positioning code, each of the high band channel receiver and the low band channel receiver being capable of receiving L₁ and L₂ respectively with precision and mitigating ionospheric effects from L₁ and L₂ respectively, L₁ having a higher frequency than L₂;

a channel emulator to emulate a channel between a transmitter of an input signal and the RF receiver, the input signal including an undesired in-band signal component and a desired signal component, and the channel emulator having a sampled version of the undesired in-band signal component fed as an input thereto; and

an adaptive filter having parameters capable of being varied based on the input signal being fed as a reference input thereto to vary a frequency of a correlated reference signal filtered therethrough, the correlated reference signal being generated based on a correlation between the input signal and the undesired in-band signal component,

wherein the filtered signal from the adaptive filter is configured to be subtracted from an output of the channel emulator to remove the in-band signal component from the input signal.

14. A method comprising:

mixing an input signal including a desired signal component and an interference signal component close in frequency to the desired signal component down to an Intermediate Frequency (IF) through an RF receiver to reduce an interference bandwidth to account for during image rejection; and

folding the interference signal component and the desired signal component during the image rejection through an image reject mixer of the RF receiver such that the interference signal component is out-of-band with respect to the desired signal component;

wherein the RF receiver is at least one of a high band channel receiver and a low band channel receiver;

wherein the high band channel receiver is configured to receive a Global Positioning System (GPS) carrier signal L₁ carrying a standard positioning code along with navigational data, and the low band channel receiver is configured to receive a GPS carrier signal L₂ carrying a precision positioning code, each of the high band channel receiver and the low band channel receiver being capable of receiving L₁ and L₂ respectively with precision and mitigating ionospheric effects from L₁ and L₂ respectively, L₁ having a higher frequency than L₂.

15. The method of claim 14, further comprising:

providing a highly linear front end in the RF receiver;

implementing a high ENOB ADC circuit in the RF receiver;

sampling, through the high ENOB ADC circuit, at a frequency having harmonics that do not coincide with the desired signal component of the input signal of the RF receiver to eliminate spurs within a data bandwidth of the RF receiver; and

simultaneously accommodating the desired signal component and the interference signal component in the RF receiver based on an increased dynamic range of the RF receiver and the high ENOB ADC circuit provided through the highly linear front end and the high ENOB ADC circuit.

16. The method of claim 14,

wherein the RF receiver includes an RF mixer and the image reject mixer in a double superheterodyne configuration thereof, and

wherein the method further comprises providing a clock signal to the high ENOB ADC circuit divided down in frequency from an output of a VCO providing a local oscillator reference signal to the image reject mixer to reduce a jitter thereof.

17. The method of claim 16, further comprising at least one of:

controlling a gain of at least one of a VGA utilized to amplify an output of the RF mixer and a VGA utilized to amplify an output of the image reject mixer through an AGC circuit provided in a feedback path of the image reject mixer.

18. A wireless system comprising:

a wireless transmitter; and

a wireless RF receiver configured to receive an input signal from the wireless transmitter, the input signal including a desired signal component and an interference signal component, the interference signal component having a power level at least 60 dB higher than that of the desired signal component, and the wireless RF receiver comprising;

a highly linear front end, and

a 12 ENOB ADC circuit along with the highly linear front end to enable the wireless RF receiver have a dynamic range of at least 60 dB, a sampling frequency of the 12 ENOB ADC circuit having harmonics that do not coincide with the desired signal component to eliminate spurs within a data bandwidth of the wireless RF receiver;

wherein the wireless RF receiver is configured to simultaneously accommodate the desired signal component and the interference signal component based on an increased dynamic range of the wireless RF receiver and the 12 ENOB ADC circuit provided through the highly linear front end and the 12 ENOB ADC circuit;

wherein the wireless RF receiver further comprises an image reject mixer at an IF stage thereof at whose image frequency location the simultaneously accommodated interference signal component is placed to reduce a power level thereof;

wherein the wireless RF receiver is at least one of a high band wireless RF receiver and a low band wireless RF receiver; and

wherein the high band channel receiver is configured to receive a Global Positioning System (GPS) carrier signal L₁ carrying a standard positioning code along with navigational data, and the low band channel receiver is configured to receive a GPS carrier signal L₂ carrying a precision positioning code, each of the high band channel receiver and the low band channel receiver being capable of receiving L₁ and L₂ respectively with precision and mitigating ionospheric effects from L₁ and L₂ respectively, L₁ having a higher frequency than L₂.

19. The wireless system of claim 18,

wherein the wireless RF receiver includes an RF mixer and the image reject mixer in a double superheterodyne configuration thereof, and

wherein a clock signal to the 12 ENOB ADC circuit is divided down in frequency from an output of a VCO providing a local oscillator reference signal to the image reject mixer to reduce a jitter thereof.

20. The wireless system of claim 19, further comprising:

an AGC circuit provided in a feedback path of the image reject mixer to control a gain of at least one of a VGA utilized to amplify an output of the RF mixer and a VGA utilized to amplify an output of the image reject mixer.

21. The wireless system of claim 18, wherein the image reject mixer is based on a Hartley architecture.

22. The wireless system of claim 18, wherein the wireless RF receiver is a GPS receiver.

23. The wireless system of claim 18, wherein the wireless system is one of a cellular transceiver and a Wi-Fi transceiver.