Sample data band-pass filter device
First Claim
1. A signal processing system comprising, in combination:
- a sampled-data band-pass filter means connected to receive an unattenuated input signal at a frequency included within an interval comprised between a first frequency (fsL) and a second frequency (fsH), which encompass a third frequency (fsO);
said sampled-data band-pass filter means including a sampler means operating at a sampling frequency (fs) and band-pass means,said sampler means automatically performing a low-frequency shift of said unattenuated input signal which emcompasses a fourth frequency (f0), wherein said sampling frequency is equal to a whole submultiple of the sum of said third frequency (fsO) and said fourth frequency (f0),said band-pass means having, as its lower cutoff frequency, the difference between the sampling frequency and the second frequency (fs-fsH) and as its upper cutoff frequency the difference between the sampling frequency and the first frequency (fs-fsL).
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Abstract
The sampled-data band-pass filter device is based on the phenomemon of aliasing, and allows the substantially unattenuated passage of the components of an input signal at a frequency included within an interval comprised between a first frequency (fsL) and a second frequency (fsH), arranged around a third frequency (fsO), while it substantially attenuates the components of the input signal at frequencies outside said interval, and furthermore automatically performs the shift to low-frequency, around a fourth frequency (fO), of the components of the input signal which have passed without attenuation. According to the invention, the device comprises, as filter element, a sampled-data band-pass filter which employs, as sampling frequency, a fifth frequency (fs) equal to a whole submultiple of a sixth frequency (nfs) equal to the sum of the third frequency (fsO) and the fourth frequency (fO), having, as lower and upper cutoff frequencies, respectively the difference between the sixth frequency and the second frequency (nfs -fsH) and the difference between the sixth frequency and the first frequency (nfs -fsL).
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Citations
5 Claims
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1. A signal processing system comprising, in combination:
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a sampled-data band-pass filter means connected to receive an unattenuated input signal at a frequency included within an interval comprised between a first frequency (fsL) and a second frequency (fsH), which encompass a third frequency (fsO);
said sampled-data band-pass filter means including a sampler means operating at a sampling frequency (fs) and band-pass means,said sampler means automatically performing a low-frequency shift of said unattenuated input signal which emcompasses a fourth frequency (f0), wherein said sampling frequency is equal to a whole submultiple of the sum of said third frequency (fsO) and said fourth frequency (f0), said band-pass means having, as its lower cutoff frequency, the difference between the sampling frequency and the second frequency (fs-fsH) and as its upper cutoff frequency the difference between the sampling frequency and the first frequency (fs-fsL). - View Dependent Claims (2, 3, 4, 5)
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Specification