Fetal heart monitoring
First Claim
1. An ultrasound fetal heart monitoring system comprising:
- an ultrasound transducer configured to generate and receive acoustic signals;
a transmit circuit configured to drive the ultrasound transducer by generating a transmit signal having a period;
a receive circuit configured to receive echo signals from the ultrasound transducer during a single gate-open interval in each period;
an analogue-to-digital converter configured to digitise the echo signals from the receive circuit; and
a processing unit configured to assign each digitised echo signal to one of several distance range bins by controlling the timing of digitisation of the analogue-to-digital converter within the single gate-open interval.
1 Assignment
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Accused Products
Abstract
A transmit amplifier (12) drives an ultrasound transducer (11) to emit a pulse, and a receive amplifier (13) amplifies the echo signal detected by the transducer. The receive amplifier'"'"'s gate opens a fixed delay after the end of the transmit pulse, and a demodulator (14) multiplies the received signal by the local oscillator signal. A low-pass filter removes the sum of the frequencies and passes the difference of the frequencies (the received signal'"'"'s Doppler frequency) to be digitized by an ADC. ADC readings are made for each of several range bins in intervals during the receive gate-open interval. One or two of the Doppler audio signals will contain the signal from the fetal heart. When a periodic signal is found, its rate is tested to see if it lies within or outside the typical range of a fetal heart.
4 Citations
20 Claims
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1. An ultrasound fetal heart monitoring system comprising:
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an ultrasound transducer configured to generate and receive acoustic signals; a transmit circuit configured to drive the ultrasound transducer by generating a transmit signal having a period; a receive circuit configured to receive echo signals from the ultrasound transducer during a single gate-open interval in each period; an analogue-to-digital converter configured to digitise the echo signals from the receive circuit; and
a processing unit configured to assign each digitised echo signal to one of several distance range bins by controlling the timing of digitisation of the analogue-to-digital converter within the single gate-open interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of using ultrasound to monitor a fetal heart comprising:
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driving a transducer using a transmit circuit, the transmit circuit generating a transmit signal having a period; receiving and amplifying echo signals received from the transducer using a receive circuit, the receive circuit having a single gate-open interval during which echo signals are received in each period; digitising the output of the receiver circuit using an analogue-to-digital converter to produce digitised echo signal values; and assigning each digitised echo signal value to one of several distance range bins by controlling the timing of the analogue-to-digital converter digitisations within the single gate-open interval using a processing unit. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification