| 摘要 |
A demodulator for use in an ultrasound information processing system is described, where in a preferred embodiment the demodulator uses a half-band filter to perform mirror-cancellation during the demodulation process. The demodulator comprises a mirror canceling quadrature mixer that mixes the input signal with quarter-sampling-frequency sinusoids and then low-pass-filters the mixed signals with half-band filters having a cutoff frequency of one-fourth the sampling frequency. In an ultrasound demodulator in accordance with a preferred embodiment, a significantly sharper mirror cancellation on the wideband input signal is achieved. Additionally, the number and complexity of mirror canceling filter operations significantly reduced, allowing for easier hardware implementation using less expensive, off-the-shelf components. Furthermore, simplified hardware for digitally providing harmonic imaging applications is achieved.
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