SIGNAL RECEPTION OF MAGNETIC RESONANCE IMAGING DEVICE

• US 20180335490A1
• Filed: 05/17/2018
• Published: 11/22/2018
• Est. Priority Date: 05/17/2017
• Status: Active Grant

• Current Assignee: Shanghai Neusoft Medical Technology Co., Ltd.
• Original Assignee: Shanghai Neusoft Medical Technology Co., Ltd.
• Inventors: ZAN, Guofeng
• Granted Patent: US 10,641,848 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 33/3621 NMR receivers or demodulators, e.g. preamplifiers, means for frequency modulation of the MR signal using a digital down converter, means for analog to digital conversion [ADC] or for filtering or processing of the MR signal such as bandpass filtering, resampling, decimation or interpolation
• CPC Class Codes: G01R 33/543 Control of the operation of the MR system, e.g. setting of acquisition parameters prior to or during MR data acquisition, dynamic shimming, use of one or more scout images for scan plane prescription G01R33/546 takes precedence

Abstract

Methods, devices, and apparatus for signal reception are provided. In one aspect, a receiver includes: a group delay circuit configured to perform a group delay on an original analog signal to obtain a group delayed analog signal, a controller configured to determine a gain mode according to an amplitude of the original analog signal, a gain circuit coupled to the group delay circuit and the controller and configured to adjust a power of the group delayed analog signal according to the determined gain mode to obtain an adjusted analog signal, an analog-to-digital converter coupled to the gain circuit and configured to perform an analog-to-digital conversion on the adjusted analog signal to generate a digital signal, and an amplitude-phase-processing circuit configured to adjust amplitude and phase of the digital signal according to the determined gain mode.

Claims

1. A receiver comprising:

a group delay circuit configured to perform a group delay on an original analog signal to obtain a group delayed analog signal;

a controller configured to determine a gain mode according to an amplitude of the original analog signal;

a gain circuit coupled to the group delay circuit and the controller and configured to adjust, according to the determined gain mode, a power of the group delayed analog signal to obtain an adjusted analog signal;

an analog-to-digital (ADC) converter coupled to the gain circuit and configured to perform an analog-to-digital conversion on the adjusted analog signal to generate a digital signal; and

an amplitude-phase-processing circuit coupled to the analog-to-digital converter and configured to adjust amplitude and phase of the digital signal according to the determined gain mode.

2. The receiver of claim 1, wherein the controller comprises:

a comparing module configured to obtain a result by comparing the amplitude of the original analog signal with a preset reference value; and

a gain controller configured to;

determine that the gain mode is a low gain mode when the result indicates that the amplitude of the original analog signal is greater than the preset reference value; and

determine that the gain mode is a high gain mode when the result indicates that the amplitude of the original analog signal is not greater than the preset reference value.

3. The receiver of claim 2, wherein the controller further comprises:

a time-sequence control module configured to, according to a sampling clock of the analog-to-digital converter, trigger the gain controller to determine the gain mode based on the result from the comparing module.

4. The receiver of claim 3, wherein the time-sequence control module is further configured to:

detect whether the analog-to-digital converter finishes the analog-to-digital conversion; and

in response to detecting that the analog-to-digital converter finishes the analog-to-digital conversion, trigger the amplitude-phase-processing circuit to adjust the amplitude and the phase of the digital signal according to the gain mode.

5. The receiver of claim 1, wherein the gain circuit is configured to switch from a current gain mode to the determined gain mode to amplify or attenuate the power of the group delayed analog signal.

6. The receiver of claim 1, wherein the receiver further comprises:

an amplitude-phase-calibrating circuit configured to determine an amplitude scaling factor and a phase compensation value of the digital signal for the amplitude-phase-processing circuit based on the determined gain mode.

7. The receiver of claim 6, wherein the amplitude-phase-calibrating circuit comprises:

a signal generating circuit configured to;

generate a reference signal of which a frequency is same as that of the original analog signal,

output the reference signal to the gain circuit under a high gain mode to obtain a first signal, and

output the reference signal to the gain circuit under a low gain mode to obtain a second signal;

an amplitude-phase-detecting circuit coupled to the gain circuit and configured to;

detect a first amplitude scaling factor and a first phase deviation value of the first signal with respect to the reference signal, and

detect a second amplitude scaling factor and a second phase deviation value of the second signal with respect to the reference signal; and

an amplitude-phase-recording module configured to record the first amplitude scaling factor and the first phase deviation value associated with the high gain mode, and

record the second amplitude scaling factor and the second phase deviation value associated with the low gain mode, and

wherein the amplitude-phase-calibrating circuit is configured to determine the amplitude scaling factor and the phase compensation value of the digital signal based on the determined gain mode, the first amplitude scaling factor and the first phase deviation value associated with the high gain mode, and the second amplitude scaling factor and the second phase deviation value associated with the low gain mode.

8. The receiver of claim 1, wherein the amplitude-phase-processing circuit is configured to:

adjust the amplitude of the digital signal according to an amplitude scaling factor corresponding to the determined gain mode, and

compensate the phase of the digital signal according to a phase compensation value corresponding to the determined gain mode.

9. The receiver of claim 1, wherein the gain mode comprises one of

a high gain mode, and

a low gain mode,

wherein an amplifying factor of the low gain mode is smaller than an amplifying factor of the high gain mode, and an attenuating factor of the low gain mode is higher than an attenuating factor of the high gain mode.

10. The receiver of claim 1, wherein the group delay circuit is configured to perform a group delay on the original analog signal for a delay time, and

wherein the delay time is greater than a sum of a first time for the controller determining the gain mode and a second time for the gain circuit to switch a current gain mode to the determined gain mode.

11. A method of receiving a signal, comprising:

performing a group delay on an original analog signal to obtain a group delayed analog signal;

determining a gain mode according to an amplitude of the original analog signal;

adjusting, according to the determined gain mode, a power of the group delayed analog signal to obtain an adjusted analog signal;

performing an analog-to-digital conversion on the adjusted analog signal to generate a digital signal; and

adjusting amplitude and phase of the digital signal according to the determined gain mode.

12. The method of claim 11, wherein determining the gain mode according to the amplitude of the original analog signal comprises:

comparing the amplitude of the original analog signal with a preset reference value to obtain a result; and

determining the gain mode to be one of a low gain mode and a high gain mode by determining whether the result indicates that the amplitude of the analog signal is greater than the preset reference value or not.

13. The method of claim 12, wherein determining the gain mode according to the amplitude of the original analog signal further comprises:

determining when to determine the gain mode based on a sampling clock corresponding to the analog-to-digital conversion.

14. The method of claim 13, further comprising:

starting to switch a current gain mode at a start moment of a sampling cycle of the sampling clock.

15. The method of claim 11, further comprising:

detecting whether the analog-to-digital conversion is completed; and

in response to detecting that the analog-to-digital conversion is completed, starting to adjust the amplitude and the phase of the digital signal according to the determined gain mode.

16. The method of claim 11, further comprising:

determining an amplitude scaling factor and a phase compensation value of the digital signal based on the determined gain mode.

17. The method of claim 16, wherein determining the amplitude scaling factor and the phase compensation value of the digital signal comprises:

generating a reference signal of which a frequency is same as that of the original analog signal;

obtaining a first signal by processing the reference signal under a high gain mode;

obtaining a second signal by processing the reference signal under a low gain mode;

determining a first amplitude scaling factor and a first phase deviation value of the first signal with respect to the reference signal;

determining a second amplitude scaling factor and a second phase deviation value of the second signal with respect to the reference signal;

determining the amplitude scaling factor based on the determined gain mode, the first amplitude scaling factor under the high gain mode and the second amplitude scaling factor under the low gain mode; and

determining the phase compensation value under the respective gain modes based on the determined gain mode, the first phase deviation value under the high gain mode and the second phase deviation value under the low gain mode.

18. The method of claim 17, wherein an amplifying factor of the low gain mode is smaller than an amplifying factor of the high gain mode, and an attenuating factor of the low gain mode is higher than an attenuating factor of the high gain mode.

19. The method of claim 11, wherein adjusting the amplitude and the phase of the digital signal according to the determined gain mode comprises:

adjusting the amplitude of the digital signal according to an amplitude scaling factor corresponding to the determined gain mode, and

compensating the phase of the digital signal according to a phase compensation value corresponding to the determined gain mode.

20. The method of claim 11, wherein performing the group delay on the analog signal comprises:

determining that a delay time is greater than a sum of a first time for determining the gain mode and a second time for switching a current gain mode to the determined gain mode; and

performing the group delay on the analog signal for the delay time.