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### Transcript

• 2. each segment of the approximated signal is compared to the original analog wave to determine the increase or decrease in relative amplitude
• 3. the decision process for establishing the state of successive bits is determined by this comparison
• 5. The demodulator can be a simple linear filter (e.g., RC or LC filter) to reconstruct the signal
• 6. The quantizer (e.g., comparator) can have full-scale outputs
• 7. The quantized value is the integral of the difference signal, which makes it less sensitive to the rate of change of the signal.</li></ul>Principle&lt;br /&gt;The principle of the ΔΣ architecture is to make rough evaluations of the signal, to measure the error, integrate it and then compensate for that error. The mean output value is then equal to the mean input value if the integral of the error is finite. A demonstration applet is available online to simulate the whole architecture. &lt;br /&gt;Variations&lt;br /&gt;There are many kinds of ADC that use this delta-sigma structure. The above analysis focuses on the simplest 1st-order, 2-level, uniform-decimation sigma-delta ADC. Many ADCs use a second-order 5-level sinc3 sigma-delta structure.&lt;br /&gt;Quantization theory formulas&lt;br /&gt;When a signal is quantized, the resulting signal approximately has the second-order statistics of a signal with independent additive white noise. Assuming that the signal value is in the range of one step of the quantized value with an equal distribution, the root mean square value of this quantization noise is&lt;br /&gt;In reality, the quantization noise is of course not independent of the signal; this dependence is the source of idle tones and pattern noise in Sigma-Delta converters.&lt;br /&gt;Oversampling ratio, where fs is the sampling frequency and 2f0 is Nyquist rate&lt;br /&gt;The rms noise voltage within the band of interest can be expressed in terms of OSR&lt;br /&gt;Adaptive Lossless Data Compression Algorithm (ALDC)&lt;br /&gt; Scope&lt;br /&gt;This ECMA standard specifies a lossless compression algorithm to reduce the number of bytes required to represent data. The algorithm is known as Adaptive Lossless Data Compression algorithm (ALDC). The numerical identifiers according to ISO/IEC 11576 allocated to this algorithm are:&lt;br /&gt;ALDC 512-Byte History Buffer: 3&lt;br /&gt;ALDC 1024-Byte History Buffer: 4&lt;br /&gt;ALDC 2048-Byte History Buffer: 5&lt;br /&gt; Definitions&lt;br /&gt;For the purposes of this ECMA Standard, the following definitions apply.&lt;br /&gt;1 Compressed Data Stream&lt;br /&gt;The output stream after encoding.&lt;br /&gt;2 Copy Pointer&lt;br /&gt;A part of the Compressed Data Stream which represents a group of two or more consecutive bytes for which there already exists an identical group in the History Buffer. It comprises a Length Code Field and a Displacement Field.&lt;br /&gt;3 Current Address&lt;br /&gt;The location within the History Buffer where the Data Byte is written.&lt;br /&gt;4 Data Byte&lt;br /&gt;The current byte of incoming data which is written into the History Buffer and is compared to all data bytes previously written into the History Buffer.&lt;br /&gt;5 Displacement Field&lt;br /&gt;That part of the Copy Pointer which specifies the location within the History Buffer of the first byte of a Matching String.&lt;br /&gt;6 End Marker&lt;br /&gt;A string of 12 ONEs indicating the end of the Compressed Data Stream.&lt;br /&gt;7 History Buffer&lt;br /&gt;A data structure where incoming data bytes are stored for use in the compression and decompression process.&lt;br /&gt;8 Literal&lt;br /&gt;A Data Byte for which no match was found in the History Buffer.&lt;br /&gt;9 Matching String&lt;br /&gt;A sequence of bytes in the incoming data which is identical with a sequence of bytes in the History Buffer.&lt;br /&gt;10 Match Count&lt;br /&gt;The number of bytes in a Matching String.&lt;br /&gt;11 Match Count Field&lt;br /&gt;That part of the Copy Pointer which specifies the number of consecutive bytes for which a match was found in the History Buffer.&lt;br /&gt;12 Pad Bits&lt;br /&gt;Bits set to ZERO and included in the Compressed Data Stream, as required, to maintain an 8-bit byte boundary.&lt;br /&gt;Conventions and Notations&lt;br /&gt;1 Representation of numbers&lt;br /&gt;The following conventions and notations apply in this Standard, unless otherwise stated.&lt;br /&gt;<ul><li>The setting of binary bits is denoted by ZERO and ONE.
• 8. Numbers in binary notation and bit combinations are represented by ZEROs and ONEs with the most significant
• 9. bit to the left.