Representation: **freq


Humdrum Representation for Frequency

REPRESENTATION

**freq – frequency representation

DESCRIPTION

The **freq representation can be used to represent frequencies for pure or complex tones. **freq distinguishes three types of tokens: frequencies, rests, and barlines. Frequencies are encoded in hertz (Hz) where 440 Hz means 440 cycles per second. Frequencies may be specified as integer or real values (using a decimal). In addition, **freq provides limited capabilities for representing phrasing and slurs. Barlines are represented using the “common system” for barlines – see **barlines**.

FILE TYPE

It is recommended that files containing predominantly **freq data should be given names with the distinguishing `”’ extension.

SIGNIFIERS

The following table summarizes the **freq mappings of signifiers and signifieds.

0-9 frequency (in hertz) specified as an integer
  or real value
r rest
= barline; == double barline
( slur start
) slur end
{ phrase mark (start)
} phrase mark (end)
; pause sign

Summary of ***freq** Signifiers*

EXAMPLES

A sample document is given below:

**freq **freq
*pure *complex
=1 =1
440 (440
440.9 .
880 440
.
.
=2 =2
r r
== ==
*- *-

Notice that frequencies can be either real or integer values. Rests are represented by the single letter `r’.

PERTINENT COMMANDS

The following Humdrum commands accept **freq encoded data as inputs:

**barks** translates **freq to **barks **cbr** translates **freq to **cbr **cents** translates **freq to **cents **cocho** translates **freq to **cocho **kern** translates **freq to **kern **pc** translates **freq to **pc **pitch** translates **freq to **pitch **semits** translate **freq to numerical **semits **solfg** translate **freq to numerical **solfg **specc** translate **freq to numerical **specC **tonh** translate **freq to numerical **Tonh **vox** determine active and inactive voices in a Humdrum file

The following Humdrum command produces **freq data as output:

**freq** translates **cbr, **cents, **cocho, **freq, **fret, **kern, **MIDI, **pitch, **semits, **solfg, **specC, and **Tonh to **cents

TANDEM INTERPRETATIONS

The following tandem interpretations can be used in conjunction with **freq:

pure tones *pure
complex tones *complex
meter signatures *M6/8
key signatures *k[f#c#]
key *c#:

Tandem interpretations for ***freq***

SEE ALSO

`` barlines, **cbr, **cents, **coch, **degree, **kern, **pc, **pitch, **semits, **specC, **Tonh``