# US 2013/0154635 A1 · Integrated nmr transceiver array

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- Number: US 2013/0154635 A1
- Document ID: US20130154635A1
- Status: Published application
- Kind: A1
- Application number: 13/330,880
- Filed: 2011-12-20
- Published: 2013-06-20
- Earliest claimed: 2011-12-20
- Assignees: Schlumberger Technology Corporation
- Inventors: SOUMYAJIT MANDAL; YI-QIAO SONG
- Web page: https://patentgrep.com/patent/US20130154635A1

## CPC

- 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}
- G01R 33/3678: {involving quadrature drive or detection, e.g. a circularly polarized RF magnetic field}
- G01V 3/32: operating with electron or nuclear magnetic resonance
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)

## Abstract

The present disclosure relates to an integrated nuclear magnetic resonance (NMR) transceiver array, the array including a plurality of integrated NMR transceiver circuits disposed on a single chip. At least one of the plurality of integrated NMR transceiver circuits includes a transmitter that receives and outputs a radio frequency (RF) pulse train and a receiver that receives an NMR signal.

## Claims

### Claim 1

An integrated nuclear magnetic resonance (NMR) transceiver array, the array comprising:
a plurality of integrated NMR transceiver circuits disposed on a single chip,
wherein at least one of the plurality of integrated NMR transceiver circuits comprises;
a transmitter that receives and outputs a radio frequency (RF) pulse train; and
a receiver that receives an NMR signal.

### Claim 2 (depends on 1)

The integrated NMR transceiver array of claim 1, wherein the transmitter comprises;
a duty cycle controller for varying the output power level of the RF pulse train; and
a power amplifier (PA) for driving a coil with the RF pulse train.

### Claim 3 (depends on 1)

The integrated NMR transceiver array of claim 1, wherein the receiver comprises;
a low-noise preamplifier (LNA) that differentially amplifies the received NMR signal by a first gain value;
a variable-gain amplifier (VGA) that further amplifies the received NMR by a second gain value;
a pair of differential mixers that are driven by local oscillator (LO) signals, receives the amplified received NMR signal from the VGA, and outputs a demodulated real in-phase (I) output and a quadrature (Q) output of the received NMR signal;
a phase switcher that selectively flips the polarity of the positive and negative LO signals that feed each differential mixer; and
a low pass filter (LPF) that receives the I output and the Q output from the pair of differential mixers, and filters then outputs the received NMR signal.

### Claim 4 (depends on 3)

The integrated NMR transceiver array of claim 3, wherein the receiver further comprises:
a buffer that receives the I output and the Q output from the LPF and outputs the received NMR signal off-chip

### Claim 5 (depends on 2)

The integrated NMR transceiver array of claim 2, wherein the power amplifier is a differential class-D switching power amplifier.

### Claim 6 (depends on 2)

The integrated NMR transceiver array of claim 2, wherein the coil is off-chip and is one selected from a group consisting of a planar coil, a solenoidal coil, honeycomb coil, and a spiderweb coil.

### Claim 7 (depends on 3)

The integrated NMR transceiver array of claim 3, wherein the first gain value is 41 dB and the second gain value is between −2 dB and 27 dB.

### Claim 8 (depends on 3)

The integrated NMR transceiver array of claim 3, wherein the receiver further comprises a shut down function that allows a received receiver shut down signal to completely turn off the receiver.

### Claim 9 (depends on 1)

The integrated NMR transceiver array of claim 1,
wherein the transceiver array receives a RF frequency reference clock input, the RF pulse train, an enable PA during transmit phase input, an enable LNA during receive phase input, a select LO phase input, and a receiver shut down signal from an off-chip field-programmable gate array (FPGA) for at least one of the plurality of transceiver circuits.

### Claim 10 (depends on 9)

The integrated NMR transceiver array of claim 9,
wherein the FPGA is based on one selected from a group consisting of a Static random-access memory (SRAM), Flash, electrically erasable programmable read-only memory (EEPROM), Fuse, Antifuse, and programmable read-only memory (PROM).

### Claim 11 (depends on 2)

The integrated NMR transceiver array of claim 2, wherein the transmitter outputs and drives the coil that is off-chip by first outputting and driving a matching network circuit that is disposed between the outputs of the transmitter and the inputs of the coil.

### Claim 12 (depends on 1)

The integrated NMR transceiver array of claim 1,
wherein, when the receiver outputs the received NMR signal off-chip, the NMR signal passes through an off-chip analogy to digital converter (ADC) and is then received at an off-chip field-programmable gate array (FPGA).

### Claim 13 (depends on 1)

The integrated NMR transceiver array of claim 1,
wherein the plurality of integrated NMR transceiver circuits are disposed on a single complementary metal-oxide-semiconductor (CMOS) chip.

### Claim 14

A method for using an integrated nuclear magnetic resonance (NMR) transceiver array, the method comprising:
receiving a radio frequency (RF) frequency reference clock input, a RF pulse train, an enable power amplifier (PA) during transmit phase input, an enable low-noise preamplifier (LNA) during receive phase input, a select local oscillator (LO) phase input, and a receiver shut down signal input at one of the plurality of NMR transceiver circuits for use in a transmitter and a receiver of the NMR transceiver array;
driving an off-chip coil using the transmitter with the RF pulse train;
receiving an NMR signal using the off-chip coil at the receiver;
processing the received NMR signal at the receiver using the enable PA during transmit phase input, the enable LNA during receive phase input, the select LO phase input, and the receiver shut down signal;
outputting an amplified and filtered received NMR signal from the receiver.

### Claim 15 (depends on 14)

The method of claim 14, wherein processing the received NMR signal further comprises:
differentially amplifying the received NMR signal by a first gain value using a LNA;
amplifying the received NMR by a second gain value using a variable-gain amplifier (VGA);
demodulating the received NMR into a real in-phase (I) output and a quadrature (Q) output of the received NMR signal using a pair of differential mixers;
selectively flipping the polarity of the positive and negative LO signals that feed the pair of differential mixers using a phase switcher;
filtering the received NMR signal I output and Q output through a low pass filter (LPF); and
buffering the received NMR signal I output and Q output using a buffer.

### Claim 16

A nuclear magnetic resonance (NMR) tool to be disposed downhole within a wellbore and integrated on a single printed circuit board, the NMR tool printed circuit board comprising:
a complementary metal-oxide-semiconductor (CMOS) chip comprising a transceiver array of at least one of a plurality of integrated NMR transceiver circuits;
at least one switch-based duplexer;
at least one digitally-tunable impedance matching network;
an analog-to-digital converter (ADC);
a field-programmable gate array (FPGA); and
a crystal oscillator,
wherein the NMR transceiver circuit comprises:
a transmitter that receives and outputs a radio frequency (RF) pulse train, wherein the transmitter comprises;
a duty cycle controller for varying the output power level of the RF pulse train; and
a power amplifier (PA) for driving a coil with the RF pulse train; and
a receiver that receives an NMR signal and has a shut down function that allows a received receiver shut down signal to completely turn off the receiver, wherein the receiver comprises;
a low-noise preamplifier (LNA) that differentially amplifies the received NMR signal by a first gain value;
a variable-gain amplifier (VGA) that further amplifies the received NMR by a second gain value;
a pair of differential mixers that are driven by local oscillator (LO) signals, receives the amplified received NMR signal from the VGA, and outputs a demodulated real in-phase (I) output and a quadrature (Q) output of the received NMR signal;
a phase switcher that selectively flips the polarity of the positive and negative LO signals that feed each differential mixer; and
a low pass filter (LPF) that receives the I output and the Q output from the pair of differential mixers, and filters then outputs the received NMR signal.