Integrated circuit systems and methods using block gain expansion and compression to improve the noise of analog storage in non-volatile memory cells

In an analog storage and playback system, a method comprising:

• repetitively sampling the audio input signal;
• sensing the amplitude of each group of samples;
• storing each group of samples with a scaling dependent on the highest amplitude sample in that group, and storing an indicator of the scaling associated with each group, each scaling being selected from a predetermined group of possible scalings, the scaling associated with the storing of groups of samples wherein the highest amplitude sample in that group is a relatively low amplitude being given a higher scaling than the scaling associated with the storing of samples of groups of samples wherein the highest amplitude sample in that group is a relatively high amplitude;
• on playback, retrieving the stored samples and the indicators of the scaling;
• rescaling each group of samples retrieved responsive to the scaling associated with the storage of that group to construct an analog sample stream of sample values proportional to the corresponding samples of the audio input signal.

In an integrated circuit for the recording and playback of analog signals by the integrated circuit having a voltage storage range, the improvement comprising:

• first and second banks of sample and hold circuits for receiving and holding samples of an analog input signal prior to storage in nonvolatile memory in the integrated circuit;
• a reference generator configured to provide a plurality of pairs of predetermined reference voltages above and below a center of the voltage storage range;
• a plurality of comparators for comparing each reference voltage to each sample input to the sample and hold circuits;
• control logic configured to detect the reference voltage pair above and below the center of the voltage storage range within which the largest sample of each successive group of samples will fit;
• a variable gain amplifier responsive to the control logic to amplify each sample in each group of samples prior to storage;
• and,
• storage arrays for storage of the amplified samples of each group and for storage of the gain of the variable gain amplifier used to amplify the samples in the group for storage.