Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

.424 FREQUENCY MODULATION, Volume IThe /(«>) is a dimensionless transfer-voltage ratio. If 7 0utwereused instead of E ont , f (u>) would be the transfer admittance.The next step is to approximate /(«) by a finite Fourier seriesabout a)in a period O equal to or greater than the interval containingthe side-frequency voltage of (7). From (7) it is obvious that thisinterval extends from O — 2Nv) to (co + 2Nv) , a total width of 4Nv.M/() « 2 (A m cos»n=0'2irmSI(&) — u> )+ B m sin'2-77-mn(ft) — o) )(11)The notation «=> used in (11) means "approximately equals only inthe interval (w — 2Nv) g»g (o> + 2Nv) ." It is sufficient that thepartial sum represent the function only in the interval (o> 2— 2Nv) Sito Si ()The reason for expressing /(