verify_signal

Builtin index · Signal processing

result = verify_signal(x)

Input: x · Output: result

What it is

x: a real vector, Mat or Signal. Structural sanity before any of the semantic diagnostics above is worth running — deliberately narrow: it answers "are these samples a usable record", not "is this signal any good".

Overloads

One call shape — this function is not overloaded.

Code	Input	Output	Description
`result = verify_signal(x)`	`x` vector, Mat, or Signalnot documented yet	`n` Numa `Num`, sample count `inf` Num`Num`s, counts — called out separately because a single NaN makes a mean, an FFT or a filter return NaN throughout, not just at that position `finite` —a `Bool` `constant` —a `Bool`, every sample equal — reported, but not an error: a DC measurement is a real thing and a stuck channel is the caller's judgement `ok` —a `Bool` `issues` List or stringa `List` of strings naming what is wrong, empty when `ok` `duration` Num`Num`s	Returns a `Record` with fields `n` (a `Num`, sample count), `nan`, `inf` (`Num`s, counts — called out separately because a single NaN makes a mean, an FFT or a filter return NaN throughout, not just at that position), `finite` (a `Bool`), `constant` (a `Bool`, every sample equal — reported, but not an error: a DC measurement is a real thing and a stuck channel is the caller's judgement), `ok` (a `Bool`) and `issues` (a `List` of strings naming what is wrong, empty when `ok`). Given a `Signal`, two more fields — `rate` and `duration` (`Num`s) — and a rate that is zero, negative or non-finite becomes an issue, since every frequency axis derived from it would be meaningless. Named `verify_signal` rather than `verify` because a bare `verify` says nothing about what it verifies.

Examples

No documentation example calls this form yet. The Signal processing chapter is where one belongs.

How it works

verify_signal(x) -- structural sanity before any semantic diagnostic above is worth running. Named verify_signal rather than verify because a bare verify says nothing about what it verifies, and this engine already has file- and hash-shaped things that would want the name. Deliberately narrow: it answers "are these samples a usable record", not "is this signal any good". NaN is called out separately from infinity because they fail differently -- a single NaN makes a mean, an FFT or a filter return NaN THROUGHOUT, not just at that position, which is how one bad sample becomes a whole bad analysis with nothing to show for it. A constant record is reported as constant and is NOT an error: a DC measurement is a real thing, and a stuck channel is for the caller to judge. Given a Signal, the sample rate is checked too and the implied duration reported, since a rate of zero or NaN silently poisons every frequency axis derived from it.

From the note above this builtin in the interpreter, where the reasoning was written down as it was built.