Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

More documents

Recommendations

Info

frequency-modulation field test141Measurements op Peak Ignition NoiseBecause of the peculiar wave shape and large crest factor of ignitionnoise it is preferable to measure the peak signal and peak ignition noiserather than the r-m-s values in order to establish, for one thing, the
142 FREQUENCY MODULATION, Volume Ipeaks, if synchronized with an unmodulated carrier, do not show theexistence of the noise threshold. Modulation, in effect, de-tunes thereceiver and the threshold becomes evident. De-tuning the receiverin the absence of modulation is one expedient which produces a similarresult and was the method used in obtaining the data shown on Figure28.Of particular interest in this figure isthe rating of the signal-tonoiseratio as shown at the right.A 30 db signal-to-noise ratio, whenmeasured with peak values, is equivalent to a 40 db r-m-s signal-to-noiseratio. Even with as low a signal-to-ignition-noise ratio as 20 db theservice is quite fair,although the ignition would be noticeable withoutmodulation. The relative infrequency of ignition peaks produces anaudible result which is very deceiving. With signal-to-ignition-noiseratios of 10 or 12 db, service is still not completely ruined but could betolerated if there were a special interest inthe program material.In general, ignition noise is transient, lasting for only a matter ofseconds as a car passes by a residence. During that period the noise isnot distressing. Furthermore, over a period of years, it may be expectedthat automobile ignition systems will be provided with suppressorswhich will reduce the u-h-f interference by at least 20 db.Ignitionnoise is of particular concern and is the predominant noise in suburbanareas.In urban areas, the field intensity from a F-M station or an A-Mstation will ordinarily be high enough to over-ride the higher noiselevels experienced. Figure 28 represents some of the results obtainedwith 56 peak microvolts per meter noise. The method of making thesemeasurements was not ideal in all respects but the data is indicativeof the results obtained in the presence of ignition noise. The curve ofFigure 29 shows r-m-s ignition noise measurements made without modulationand illustrates that no threshold is found under such conditions.Since a system is of no value until modulated, this curve is shown onlyto illustrate the point that the noise threshold must be associated withmodulation.Figure 30 presents interesting data showing peak ignition noisemeasurements made with an 8-kc audio band width. Peak noise inputmicrovolts are plotted against peak S/N ratio, the field intensity of thestation remaining unchanged. The signal with which the noise wascompared was 100 per cent 400-cycle tone modulation. The noise sourcein this case was an automobile ignition system built up and mountedon a lathe at Bellmore. The battery power was not varied to producedifferent field intensities of noise because this method changed the characterof the noise. The field intensity was varied over a very widerange, without changing its normal characteristic, by orienting and
Page 2 and 3:
FREQUENCY MODULATIONVolume IEdited
Page 4:
1000-3000 watt FM transmitter—194
Page 8 and 9:
:FREQUENCY MODULATIONVolume ICONTEN
Page 10 and 11:
FREQUENCY MODULATION NOISECHARACTER
Page 12 and 13:
NOISE CHARACTERISTICS 3w na - (u—
Page 14 and 15:
NOISE CHARACTERISTICS 6to the ratio
Page 16 and 17:
NOISE CHARACTERISTICS 7where C = ca
Page 18 and 19:
•NOISE CHARACTERISTICS 9nF naF in
Page 20 and 21:
NOISE CHARACTERISTICS 112G-)F1 aJ.
Page 22 and 23:
ecurrent impulse. It isNOISE CHARAC
Page 24 and 25:
NOISE CHARACTERISTICS 15constant sh
Page 26 and 27:
NOISE CHARACTERISTICS 17/ 1 d(t)- (
Page 28 and 29:
NOISE CHARACTERISTICS 19modulation
Page 30 and 31:
.NOISE CHARACTERISTICS 21vary direc
Page 32 and 33:
NOISE CHARACTERISTICS 23and frequen
Page 34 and 35:
1NOISE CHARACTERISTICS 25curves for
Page 36 and 37:
NOISE CHARACTERISTICS 27not conveni
Page 38 and 39:
NOISE CHARACTERISTICS 29lation rece
Page 40 and 41:
NOISE CHARACTERISTICS 31theoretical
Page 42 and 43:
NOISE CHARACTERISTICS 33sponding or
Page 44 and 45:
NOISE CHARACTERISTICS 35modulation
Page 46 and 47:
NOISE CHARACTERISTICS 37signal was
Page 48 and 49:
NC1SE CHARACTERISTICS .39Since the
Page 50 and 51:
NOISE CHARACTERISTICS 41tude modula
Page 52 and 53:
NOISE CHARACTERISTICS 43frequency m
Page 54 and 55:
phase modulation maintained constan
Page 56 and 57:
FREQUENCY MODULATION 47band pass of
Page 58 and 59:
FREQUENCY MODULATION 49IV.Interfere
Page 60 and 61:
FREQUENCY MODULATION 61frequency in
Page 62 and 63:
FREQUENCY MODULATION 53maximum perm
Page 64 and 65:
FREQUENCY MODULATION 55Frequency Mo
Page 66 and 67:
BAND WIDTH AND READABILITY INFREQUE
Page 68 and 69:
BAND WIDTH AND READABILITY 59The re
Page 70 and 71:
BAND WIDTH AND READABILITY 61Listen
Page 72 and 73:
BAND WIDTH AND READABILITY 63The cu
Page 74 and 75:
VARIATION OF BANDWIDTH WITH MODULAT
Page 76 and 77:
VARIATION OF BANDWIDTH 67
Page 78 and 79:
VARIATION OF BANDWIDTH0.0606 4998 7
Page 80 and 81:
iVARIATION OF BANDWIDTH 71Example:
Page 82 and 83:
ItVARIATION OF BANDWIDTH 73where 6
Page 84:
whereVARIATION OF BANDWIDTHmEn=—
Page 87 and 88:
78 FREQUENCY MODULATION, Volume I»
Page 89 and 90:
x80 FREQUENCY MODULATION, Volume IJ
Page 91 and 92:
82 FREQUENCY MODULATION, Volume I
Page 93 and 94:
84 FREQUENCY MODULATION, Volume IGE
Page 95 and 96:
86 FREQUENCY MODULATION, Volume Imo
Page 97 and 98:
88 FREQUENCY MODULATION, Volume Ico
Page 99 and 100: 90 FREQUENCY MODULATION, Volume IFo
Page 101 and 102: 92 FREQUENCY MODULATION, Volume Iau
Page 103 and 104: 94 FREQUENCY MODULATION, Volume Ita
Page 105 and 106: 96 FREQUENCY MODULATION, Volume Iwl
Page 107 and 108: 98 FREQUENCY MODULATION, Volume Iwa
Page 109 and 110: :100 FREQUENCY MODULATION, Volume I
Page 111 and 112: 102 FREQUENCY MODULATION, Volume Id
Page 113 and 114: 104 FREQUENCY MODULATION, Volume Ie
Page 115 and 116: 106 FREQUENCY MODULATION, Volume Ia
Page 117 and 118: 108 FREQUENCY MODULATION, Volume Ip
Page 119 and 120: 110 FREQUENCY MODULATION, Volume It
Page 121 and 122: 112 FREQUENCY MODULATION, Volume Io
Page 123 and 124: :114 FREQUENCY MODULATION, Volume I
Page 125 and 126: —110 FREQUENCY MODULATION, Volume
Page 127 and 128: 118 FREQUENCY MODULATION, Volume If
Page 129 and 130: 120 FREQUENCY MODULATION, Volume Ic
Page 131 and 132: 122 FREQUENCY MODULATION, Volume Im
Page 133 and 134: 124 FREQUENCY MODULATION, Volume IO
Page 135 and 136: 126 FREQUENCY MODULATION, Volume II
Page 139 and 140: 130 FREQUENCY MODULATION, Volume Ie
Page 143 and 144: 134 FREQUENCY MODULATION, Volume Il
Page 145 and 146: 136 FREQUENCY MODULATION, Volume 1n
Page 147 and 148: 138 FREQUENCY MODULATION, Volume Ii
Page 149: 140 FREQUENCY MODULATION, Volume IT
Page 153 and 154: 144 FREQUENCY MODULATION, Volume In
Page 165 and 166: 156 FREQUENCY MODULATION, Volume Iu
Page 167 and 168: 158 FREQUENCY MODULATION, Volume IE
Page 169 and 170: IMODULATO*160 FREQUENCY MODULATION,
Page 171 and 172: 162 FREQUENCY MODULATION, Volume IT
Page 173 and 174: cos164 FREQUENCY MODULATION, Volume
Page 175 and 176: '166 FREQUENCY MODULATION, Volume I
Page 177 and 178: 168 FREQUENCY MODULATION, Volume Iu
Page 181 and 182: 172 FREQUENCY MODULATION, Volume IS
Page 185 and 186: 176 FREQUENCY MODULATION, Volume Iw
Page 187 and 188: A PRETUNED TURNSTILE ANTENNA*tByGeo
Page 189 and 190: 180 FREQUENCY MODULATION, Volume IF
Page 193 and 194: 184 FREQUENCY MODULATION, Volume Is
Page 195 and 196: 186 FREQUENCY MODULATION, Volume 1f
Page 197 and 198: 188 FREQUENCY MODULATION, Volume 1M
Page 199 and 200: 190 FREQUENCY MODULATION, Volume Is
Page 201 and 202:
192 FREQUENCY MODULATION, Volume I1
Page 203 and 204:
CHARACTERISTICS OF THE PYLON FM ANT
Page 205 and 206:
196 FREQUENCY MODULATION, Volume IA
Page 207 and 208:
198 FREQUENCY MODULATION, Volume Is
Page 209 and 210:
1200 FREQUENCY MODULATION, Volume-A
Page 211 and 212:
202 FREQUENCY MODULATION, Volume IR
Page 213 and 214:
204 FREQUENCY MODULATION, Volume IF
Page 215 and 216:
206 FREQUENCY MODULATION, Volume II
Page 217 and 218:
::208 FREQUENCY MODULATION, Volume
Page 219 and 220:
_.'___.._210 FREQUENCY MODULATION,
Page 221 and 222:
212 FREQUENCY MODULATION, Volume Im
Page 223 and 224:
:..=214 FREQUENCY MODULATION, Volum
Page 225 and 226:
216 FREQUENCY MODULATION, Volume Io
Page 227 and 228:
218 FREQUENCY MODULATION, Volume IT
Page 229 and 230:
220 FREQUENCY MODULATION, Volume Jl
Page 231 and 232:
222 FREQUENCY MODULATION, Volume Ii
Page 233 and 234:
Page 235 and 236:
i226 FREQUENCY MODULATION, Volume I
Page 237 and 238:
228 FREQUENCY MODULATION, Volume Ic
Page 239 and 240:
IMPULSE NOISE IN F-M RECEPTIONSByVe
Page 241 and 242:
232 FREQUENCY MODULATION, Volume 1o
Page 243 and 244:
234 FREQUENCY MODULATION, Volume Ia
Page 245 and 246:
236 FREQUENCY MODULATION, Volume Iv
Page 247 and 248:
Page 249 and 250:
240 FREQUENCY MODULATION, Volume In
Page 251 and 252:
:242 FREQUENCY MODULATION, Volume I
Page 253 and 254:
Page 255 and 256:
246 FREQUENCY MODULATION, Volume It
Page 257 and 258:
Page 259 and 260:
Page 261 and 262:
Page 263 and 264:
Page 265 and 266:
Page 267 and 268:
'United258 FREQUENCY MODULATION, Vo
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
264 FREQUENCY MODULATION, Volume I-
Page 275 and 276:
Page 277 and 278:
268 FREQUENCY MODULATION, Volume IN
Page 279 and 280:
270 FREQUENCY MODULATION, Volume Iq
Page 281 and 282:
I272 FREQUENCY MODULATION, Volume I
Page 283 and 284:
Page 285 and 286:
;276 FREQUENCY MODULATION, Volume 1
Page 287 and 288:
Page 289 and 290:
=280 FREQUENCY MODULATION, Volume I
Page 291 and 292:
282 FREQUENCY MODULATION, Volume 1F
Page 293 and 294:
+[\284 FREQUENCY MODULATION, Volume
Page 295 and 296:
Page 297 and 298:
Page 299 and 300:
290 FREQUENCY MODULATION, Volume 1C
Page 301 and 302:
Page 303 and 304:
Page 305 and 306:
296 FREQUENCY MODULATION, Volume Il
Page 307 and 308:
298 FREQUENCY MODULATION, Volume IR
Page 309 and 310:
Page 311 and 312:
Page 313 and 314:
304 FREQUENCY MODULATION, Volume I=
Page 315 and 316:
Page 317 and 318:
Page 319 and 320:
Page 321 and 322:
312 FREQUENCY MODULATION, Volume Id
Page 323 and 324:
Page 325 and 326:
Page 327 and 328:
318 FREQUENCY MODULATION, Volume 1r
Page 329 and 330:
320 FREQUENCY MODULATION, Volume Iw
Page 331 and 332:
,322 FREQUENCY MODULATION, Volume 1
Page 333 and 334:
-324 FREQUENCY MODULATION, Volume I
Page 335 and 336:
.326 FREQUENCY MODULATION, Volume 1
Page 337 and 338:
328 FREQUENCY MODULATION, Volume 1
Page 339 and 340:
Page 341 and 342:
332 FREQUENCY MODULATION, Volume IC
Page 343 and 344:
Page 345 and 346:
Page 347 and 348:
33dFREQUENCY MODULATION, Volume ITh
Page 349 and 350:
Page 351 and 352:
'342 FREQUENCY MODULATION, Volume 1
Page 353 and 354:
'344 FREQUENCY MODULATION, Volume I
Page 355 and 356:
e346 FREQUENCY MODULATION, Volume I
Page 357 and 358:
348FREQUENCY MODULATION, Volume ILe
Page 359 and 360:
Page 361 and 362:
352 FREQUENCY MODULATION, Volume I+
Page 363 and 364:
}354 FREQUENCY MODULATION, Volume I
Page 365 and 366:
356 FREQUENCY MODULATION, Volume I+
Page 367 and 368:
THE RATIO DETECTOR*!ByStuart Wm. Se
Page 369 and 370:
Page 371 and 372:
Page 373 and 374:
Page 375 and 376:
Page 377 and 378:
Page 379 and 380:
Page 381 and 382:
Page 383 and 384:
Page 385 and 386:
Page 387 and 388:
378 FREQUENCY MODULATION, Volume IE
Page 389 and 390:
Page 391 and 392:
382 FREQUENCY MODULATION, Volume Ig
Page 393 and 394:
Page 395 and 396:
Page 397 and 398:
Page 399 and 400:
390 FREQUENCY MODULATION, Volume IM
Page 401 and 402:
——392 FREQUENCY MODULATION, Vol
Page 403 and 404:
Page 405 and 406:
DUPLEX TRANSMISSION OF FREQUENCY-MO
Page 407 and 408:
I398 FREQUENCY MODULATION, Volume I
Page 409 and 410:
Page 411 and 412:
Page 413 and 414:
Page 415 and 416:
Page 417 and 418:
408 FREQUENCY MODULATION, Volume Ir
Page 419 and 420:
USE OF SUBCARRIER FREQUENCY MODULAT
Page 421 and 422:
412 FREQUENCY MODULATION, Volume Iv
Page 423 and 424:
Page 425 and 426:
Page 427 and 428:
Page 429 and 430:
i420 FREQUENCY MODULATION, Volume 1
Page 431 and 432:
Page 433 and 434:
.424 FREQUENCY MODULATION, Volume I
Page 435 and 436:
Page 437 and 438:
428 FREQUENCY MODULATION, Volume Ij
Page 439 and 440:
430 FREQUENCY MODULATION, Volume Ib
Page 441 and 442:
432 FREQUENCY MODULATION, Volume 1
Page 443 and 444:
434 FREQUENCY MODULATION, Volume If
Page 445 and 446:
Page 447 and 448:
Page 449 and 450:
Page 451 and 452:
:.442 FREQUENCY MODULATION, Volume
Page 453 and 454:
Page 455 and 456:
..446 FREQUENCY MODULATION, Volume
Page 457 and 458:
448 FREQUENCY MODULATION, Volume Iq
Page 459 and 460:
eis450 FREQUENCY MODULATION, Volume
Page 461 and 462:
—PUSH-PULL FREQUENCY MODULATED CI
Page 463 and 464:
Page 465 and 466:
456 FREQUENCY MODULATION, Volume IS
Page 467 and 468:
Page 469 and 470:
Page 471 and 472:
Page 473 and 474:
Page 475 and 476:
Page 477 and 478:
Page 479 and 480:
Page 481 and 482:
.let472 FREQUENCY MODULATION, Volum
Page 483 and 484:
Page 485 and 486:
Page 487 and 488:
478 FREQUENCY MODULATION, Volume IC
Page 489 and 490:
Page 491 and 492:
. 2•482FREQUENCY MODULATION, Volu
Page 493 and 494:
ii484FREQUENCY MODULATION, Volume I
Page 495 and 496:
Page 497 and 498:
Page 499 and 500:
Page 501 and 502:
492 FREQUENCY MODULATION, Volume IS
Page 503 and 504:
«/„I|J494 FREQUENCY MODULATION,
Page 505 and 506:
i'Iea496FREQUENCY MODULATION, Volum
Page 507 and 508:
6a—498 FREQUENCY MODULATION, Volu
Page 509 and 510:
Page 511 and 512:
502 FREQUENCY MODULATION, Volume 1C
Page 513 and 514:
Page 516 and 517:
APPENDIX IFREQUENCY MODULATIONA Bib
Page 518 and 519:
FREQUENCY MODULATION BIBLIOGRAPHY"F
Page 520 and 521:
FM BIBLIOGRAPHY 511"Input Impedance
Page 522 and 523:
APPENDIX IIFM STATION PLACEMENT AND
Page 524:
STATION PLACEMENT AND FIELD SURVEY
show all

Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?