Chopper mixer telemetry circuit
First Claim
1. A wireless receiver comprising:
- a first mixer amplifier that receives a telemetry signal modulated at a clock frequency, amplifies the telemetry signal to produce a first amplified signal, demodulates the first amplified signal at the clock frequency to produce a first demodulated signal, and extracts a portion of the first demodulated signal to produce a first output signal;
a second mixer amplifier that receives the same telemetry signal as the first mixer amplifier, amplifies the telemetry signal to produce a second amplified signal, demodulates the second amplified signal at the clock frequency to produce a second demodulated signal that is approximately 90 degrees out of phase with the first demodulated signal, and extracts a portion of the second demodulated signal to produce a second output signal; and
circuitry that produces a third output signal based on the first and second output signals.
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Abstract
This disclosure describes a chopper mixer telemetry circuit for use in a wireless receiver. The receiver may be located in an implantable medical device (IMD) or external programmer. The chopper mixer telemetry circuit may include a mixer amplifier that operates as a synchronous demodulator to provide selective extraction of wireless signals received from a transmitter while suppressing out-of-band noise that can undermine the reliability of the telemetry link between an IMD or programmer and another device. The mixer amplifier may utilize parallel signal paths to convert the received telemetry signal into an in-phase (I) signal component and a quadrature (Q) signal component and recombine the I and Q signal components to reconstruct the total signal independently of the phase mismatch between the transmitter and receiver. Each signal path may include a chopper-stabilized mixer amplifier that amplifies telemetry signals within a desired band while suppressing out-of-band noise.
156 Citations
30 Claims
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1. A wireless receiver comprising:
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a first mixer amplifier that receives a telemetry signal modulated at a clock frequency, amplifies the telemetry signal to produce a first amplified signal, demodulates the first amplified signal at the clock frequency to produce a first demodulated signal, and extracts a portion of the first demodulated signal to produce a first output signal; a second mixer amplifier that receives the same telemetry signal as the first mixer amplifier, amplifies the telemetry signal to produce a second amplified signal, demodulates the second amplified signal at the clock frequency to produce a second demodulated signal that is approximately 90 degrees out of phase with the first demodulated signal, and extracts a portion of the second demodulated signal to produce a second output signal; and circuitry that produces a third output signal based on the first and second output signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16)
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9. A method comprising:
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receiving a wireless, modulated telemetry signal; amplifying the modulated telemetry signal to produce a first amplified signal; demodulating the first amplified signal at a clock frequency to produce a first demodulated signal; extracting a portion of the first demodulated signal to produce a first output signal; amplifying the same modulated telemetry signal that was amplified to produce the first amplified signal to produce a second amplified signal; demodulating the second amplified signal at the clock frequency to produce a second demodulated signal that is 90 degrees out of phase with the first demodulated signal; extracting a portion of the second demodulated signal to produce a second output signal; and producing a third output signal based on the first and second output signals.
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17. An apparatus comprising:
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means for receiving a wireless, modulated telemetry signal; means for amplifying the modulated telemetry signal to produce a first amplified signal; means for demodulating the first amplified signal at a clock frequency to produce a first demodulated signal; means for extracting a portion of the first demodulated signal to produce a first output signal; means for amplifying the same modulated telemetry signal that was amplified to produce the first amplified signal to produce a second amplified signal; means for demodulating the second amplified signal at the clock frequency to produce a second demodulated signal that is 90 degrees out of phase with the first demodulated signal; means for extracting a portion of the second demodulated signal to produce a second output signal; and means for producing a third output signal based on the first and second output signals. - View Dependent Claims (18, 19, 20)
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21. An implantable medical device (IMD) comprising:
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a first mixer amplifier that receives a telemetry signal modulated at a clock frequency, amplifies the telemetry signal to produce a first amplified signal, demodulates the first amplified signal at the clock frequency to produce a first demodulated signal, and extracts a portion of the first demodulated signal to produce a first output signal; a second mixer amplifier that receives the same telemetry signal as the first mixer amplifier, amplifies the telemetry signal to produce a second amplified signal, demodulates the second amplified signal at the clock frequency to produce a second demodulated signal that is approximately 90 degrees out of phase with the first demodulated signal, and extracts a portion of the second demodulated signal to produce a second output signal; and quadrature reconstruction circuitry that combines the first and second output signals to produce a third output signal, the third output signal being an amplified representation of the telemetry signal. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification