[sdiy] analogue phase modulation

[Andre Majorel]

On 2007-01-09 23:30 +0100, JH. wrote:

> What amount of (maximum) phase modulation depth (number of
> periods), do typical digital PM sounds a la DX7 etc. have ?

This might or might not answer your question but... In John
Chowning and David Bristow's book _FM_Theory_&_Applications_,
appendix 2 gives a table of modulation index vs. operator output
level values.

Model	OL	MI

DX7	10	0.003
	20	0.013
	30	0.031
	...
	95	9.263
	99	13.119

DX21	10	0.004
	...
	95	17.773
	99	25.136

CX5	20	0.003
	...
	120	6.853
	127	12.570

The modulation index is defined on page 56 as delta_f / f_m where
delta_f is the frequency deviation above and below the average
frequency of the carrier and f_m is the modulating frequency.

-- 
André Majorel <URL:http://www.teaser.fr/~amajorel/>
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