**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

A sample document is given below:

**freq	**freq
*pure	*complex
=1	=1
440	(440
440.9	.
880	440
263.	.
.	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

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

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

• Pertinent description in the Humdrum User Guide
• Index to Humdrum Representations
• Index to Humdrum Commands
• Table for Contents for Humdrum User Guide