What is Sample Compression?
The X34 implements run length sample compression. The standard scheme for logic analyzers is to store samples in a circular buffer. Even if consecutive samples are identical, they are still stored in the buffer. For systems with continuous activity on the input signals, this makes sense. But for systems which exhibit intermittent bursts of activity, the standard scheme can result in very inefficient use of storage. With sample compression, the analyzer stores a count along with each sample. During bursts of activity, just about every sample will be stored, along with a count value which will typically be 1. In the gaps between bursts, a single sample will be stored, along with a count value. This sample compression scheme is implemented in the first release of the X34 firmware. We can compress even more. If only a few signals are changing, and particularly if we have runs of less than a few hundred identical samples, we can implement per-byte run length compression, with a variable-len
The Ant18e implements run length sample compression. The standard scheme for logic analyzers, including the Ant8 and the Ant16, is to store samples in a circular buffer. Even if consecutive samples are identical, they are still stored in the buffer. For systems with continuous activity on the input signals, this makes sense. But for systems which exhibit intermittent bursts of activity, the standard scheme can result in very inefficient use of storage. With sample compression, the Ant18e stores a count along with each sample. During bursts of activity, just about every sample will be stored, along with a count value which will typically be 1. In the gaps between burst, a single sample will be stored, along with a potentially large count value. This increases the effective buffer depth of the Ant18e when sampling bursty signals to a million or more samples.
