Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

' '_J__''COMMON- AND ADJACENT-CHANNEL INTERFERENCE 345~1 Ux 5x 4 7x 6 105z 105x8a ' " ~ 4 (4 ~ 128~ 512~ 16384~'J\(41)a> ~ 8" r~ 16 ~ 128~~1024 ~ 16384~ ')(42)2£. 4 5 1 —- 21a;4 _ ^L 6 429x8° 4 ~~ ~~64 1 20 ~ 320 ~ 1280 ~ 32768'a - 2 (- l)" l1(3)- (2wa " A M nl- D { £! i ^J_ ,J (43)\?!J 2- + X t*ra ft!2 2 * (n+1) (n + 2) ... (n+fc))( }This expression for a„ was previously obtained by Vigoureux 19 andMoullin 20In the limit as x — > 1:Envelope = V2 e i V1 + cos 2ir\d = 2e i | cos ir(j.(|= — h+|cos 0- i cos 207T { 3 15+ S cos39 -I cos49 -}= — Ji _ 2 2 (- 1 )" cos w6 ?7T i „ = 1 (2«) 2 - 1 \where = 2iry£. (45)Calculation of Average Value of Instantaneous FrequencyConsider the integral:'IT\L I X 2 + X COS £7T J 1 + X 2 + 2x COS £1 — t1ds (46)2dtMake the transformation: cos s = -, d £1 + t-' ' 1 + t*19F. M. Colebrook, "A Note on the Frequency Analysis of the HeterodyneEnvelope. Its Relation to Problems of Interference." Wireless Engineer & ExperimentalWireless, Vol. 9, p. 200, April, 1932.20E. B. Moullin, "The Detection by a Straight Line Rectifier of Modulatedand Heterodyne Signals," Wireless Engineer & Experimental Wireless, Vol. 9,pp. 378-383; July, 1932.