Data compression apparatus and method for data recorder

A method of compressing a digital input information signal to reduce storage requirements, transmission bandwidth, or the like, comprising the steps of:

• (1) receiving a predetermined number n of input data samples representing said input information signal during a sampling period;
• (2) analyzing said predetermined number n of input data samples and determining a compression parameter corresponding to the magnitude of an information parameter of said input information signal;
• (3) selecting a predetermined portion of said data samples as a function of said compression parameter to provide a second predetermined number r of compressed data samples;
• (4) providing a compressed data string comprising said compression parameter and said predetermined number r compressed data samples;
• (5) obtaining a reconstructed input signal from said r compressed data samples;
• (6) comparing said reconstructed input signal to said input information signal;
• and
• (7) adjusting the number r in response to the comparing step so that said reconstructed input signal matches said input information signal within a predetermined error.

Apparatus for compression of digital data, comprising:

• input means for receiving a predetermined number n of input data samples, each of said data samples comprising a data word having a predetermined number m of bits;
• signal processing means for analyzing said predetermined number n of input data samples and for determining a compression parameter corresponding to the magnitudes of said predetermined number n of input data samples;
• compression means responsive to said compression parameter for selecting a predetermined number k bits of each one of said data samples, where k is less than m, to provide said predetermined number n of k-bit compressed data samples;
• and
• output means for providing a compressed data stream comprising said compression parameter and said predetermined number of k-bit compressed data samples.

A method for compressing digital data to reduce storage requirements, transmission bandwidth, or the like, comprising the steps of:

• (a) receiving a predetermined number n of input data samples, each of said data samples comprising a data word having a predetermined number m of bits;
• (b) determining a compression parameter corresponding to the magnitude of said predetermined number n of input data samples;
• (c) selecting a predetermined number k bits of each one of said data samples, where k is less than m, corresponding to the magnitude of said compression parameter to provide said predetermined number n of k-bit compressed data samples;
• and
• (d) providing a compressed data stream comprising said compression parameter and said p redetermined number n of k-bit compressed data samples.

Apparatus for compression of digital data, comprising:

• input means for receiving a predetermined number n of input data samples, each of said data samples comprising a data word having a predetermined number m of bits;
• first-in first-out memory means for storing said predetermined number n of input data samples and for sequentially recalling said input data samples;
• encoder means responsive to each one of said predetermined number n of input data samples and for providing a p-bit gain code corresponding to the magnitude of the largest one of said predetermined number n of input data samples;
• data selector means responsive to said gain code for selecting a predetermined number k bits of each one of said input data samples recalled from said first-in first-out memory means, where k is less than m, to provide said predetermined number n of k-bit compressed data samples;
• and
• output means for providing a compressed data string comprising said gain code and said predetermined number n of k-bit compressed data samples from said data selector means.

A method of compressing a digital input information signal having a plurality of frequency components, comprising the steps of:

• (1) receiving a predetermined number n of input data samples representing said input information signal during a sampling period, said data samples having m bits;
• (2) determining a compression parameter corresponding to a preselected frequency component contained in said predetermined number n of input data samples in said input information signal;
• (3) selecting a second predetermined number r of data samples, where r is less than n, in response to said frequency compression parameter to provide said predetermined number r of compressed data samples;
• (4) determining a gain compression parameter corresponding to the magnitude of the amplitude of said input information signal during said sampling period;
• (5) selecting a predetermined number k bits of each one of said second predetermined number r of said data samples, where k is less than m, corresponding to said gain compression parameter;
• and
• (6) providing a compressed data string comprising said frequency compression parameter, said gain compression parameter, and said predetermined number r of k-bit compressed data samples.

Apparatus for compression of a digital input information signal, comprising:

• input means for receiving a predetermined number n of input data samples representing said input information signal during a sampling period, each of said data samples comprising a data word having a predetermined number m of bits;
• first signal processing means for analyzing said predetermined number n of input data samples and for determining a gain compression parameter corresponding to the magnitude of the amplitude of said input information signal during said sampling period;
• second signal processing means for analyzing said predetermined number n of input data samples and for determining a frequency compression parameter corresponding to a preselected frequency component contained in said input information signal during said sampling period;
• compression means responsive to said gain compression parameter and said frequency compression parameter for selecting a predetermined portion of said data samples to provide a second predetermined number r of compressed data samples;
• and
• output means for providing a compressed data string comprising said gain compression parameter, said frequency compression parameter, and said second predetermined number r compressed data samples.

Apparatus for compression of an input information signal, comprising:

• input means for receiving a predetermined number n of input data samples representing said input information signal during a sampling period;
• signal processing means responsive to said predetermined number n of input data samples for determining a compression parameter corresponding to the magnitude of a frequency component of said input information signal, said compression parameter comprising a frequency compression parameter corresponding to the highest frequency of interest contained in said input information signal during said sampling period, said frequency compression parameter corresponding to a frequency component exceeding a predetermined threshold magnitude contained in said input information signal during said sampling period;
• compression means responsive to said compression parameter for selecting a predetermined portion of r data samples, where r is less than n, to provide a second predetermined number r of compressed data samples;
• output means for providing a compressed data string comprising said compression parameter and said predetermined number r compressed data samples;
• means responsive to said r compressed data samples for obtaining a reconstructed input signal;
• means for comparing said reconstructed input signal to said input information signal;
• and
• means responsive to said comparing means for adjusting the number r so that said reconstructed input signal matches said input information signal within a predetermined error.

Apparatus for compression of an input information signal, comprising:

• input means for receiving a predetermined number n of input data samples representing said input information signal during a sampling period;
• signal processing means responsive to said predetermined number n of input data samples for determining a compression parameter corresponding to the magnitude of a frequency component of said input information signal, said compression parameter comprising a frequency compression parameter corresponding to the highest frequency of interest contained in said input information signal during said sampling period;
• compression means responsive to said compression parameter for selecting a predetermined portion of r data samples, where r is less than n, to provide a second predetermined number r of compressed data samples, said compression means being responsive to said frequency compression parameter for decimating said predetermined number n of data samples to obtain said predetermined number r of compressed data samples;
• output means for providing a compressed data string comprising said compression parameter and said predetermined number r compressed data samples;
• means responsive to said r compressed data samples for obtaining a reconstructed input signal;
• means for comparing said reconstructed input signal to said input information signal;
• and
• means responsive to said comparing means for adjusting the number r so that said reconstructed input signal matches said input information signal within a predetermined error.

Apparatus for compression of an input information signal, comprising:

• input means for receiving a predetermined number n of input data samples representing said input information signal during a sampling period;
• signal processing means responsive to said predetermined number n of input data samples for determining a compression parameter corresponding to the magnitude of a frequency component of said input information signal, said compression parameter comprising a frequency compression parameter corresponding to the highest frequency of interest contained in said input information signal during said sampling period,
• said signal processing means comprising Fourier transform means for providing a plurality of frequency components corresponding to the frequency spectrum of said input information signal, means for comparing each of said plurality of frequency components to a predetermined value, and means for providing said compression parameter corresponding to the highest one of said plurality of frequency components which exceeds said predetermined value;
• compression means responsive to said compression parameter for selecting a predetermined portion of r data samples, where r is less than n, to provide a second predetermined number r of compressed data samples;
• output means for providing a compressed data string comprising said compression parameter and said predetermined number r compressed data samples;
• means responsive to said r compressed data samples for obtaining a reconstructed input signal;
• means for comparing said reconstructed input signal to said input information signal;
• and
• means responsive to said comparing means for adjusting the number r so that said reconstructed input signal matches said input information signal within a predetermined error.

Apparatus for compression of an input information signal, comprising:

• input means for receiving said input information signal during a sampling period;
• analog-to-digital conversion means for converting said input information signal into said predetermined number n of input data samples;
• signal processing means responsive to said predetermined number n of input data samples for determining a compression parameter corresponding to the magnitude of an information parameter of said input information signal;
• compression means responsive to said compression parameter for selecting a predetermined portion of r data samples, where r is less than n, to provide a second predetermined number r of compressed data samples;
• output means for providing a compressed data string comprising said compression parameter and said predetermined number r compressed data samples;
• means responsive to said r compressed data samples for obtaining a reconstructed input signal;
• means for comparing said reconstructed input signal to said input information signal;
• and
• means responsive to said comparing means for adjusting the number r so that said reconstructed input signal said input information signal within a predetermined error.

Apparatus for compression of digital data, comprising:

• input means for receiving a predetermined number n of input data samples, each of said data samples comprising a data word having a predetermined number m of bits;
• signal processing means for analyzing said predetermined number n of input data samples and for determining a gain compression parameter corresponding to the magnitudes of said predetermined number n of input data samples;
• compression means responsive to said gain compression parameter for selecting a predetermined number k bits of each one of said data samples, where k is less than m, to provide said predetermined number n of k-bit compressed data samples;
• and
• output means for providing a compressed data stream comprising said gain compression parameter and said predetermined number n of k-bit compressed data samples.

Apparatus for compression of an input analog signal, comprising:

• input means for receiving a predetermined number n of input data samples, each of said data samples comprising a data word having a predetermined number m of bits;
• first-in first-out memory means for storing said predetermined number n of input data samples and for sequentially recalling said input data samples;
• encoder means responsive to each one of said predetermined number n of input data samples and for providing a p-bit gain code corresponding to the magnitude of the largest one of said predetermined number n of input data samples;
• data selector means responsive to said gain code for selecting a predetermined number k bits of each one of said input data samples recalled from said first-in first-out memory means, where k is less than m, to provide said predetermined number n of k-bit compressed data samples;
• and
• output means for providing a compressed data string comprising said gain code and said predetermined number n of k-bit compressed data samples from said data selector means, said output means comprising counter means responsive to count said predetermined number n of input data samples and to provide a period signal corresponding to the time represented by said predetermined number n of input data samples plus the time of said gain code.