CLASS 375 PULSE OR DIGITAL COMMUNICATIONS 375 - 1 375 PULSE OR DIGITAL COMMUNICATIONS 130 SPREAD SPECTRUM 228 .With indicator 131 .Hybrid form 229 EQUALIZERS 132 .Frequency hopping 230 .Automatic 133 ..End-to-end transmission system 231 ..Training period or initial set 134 ...Having specific code up acquisition or tracking 232 ..Adaptive 135 ..Transmitter 233 ...Decision feedback equalizer 136 ..Receiver 234 ...Fractionally spaced equalizer 137 ...Having specific code 235 ...Quadrature channels acquisition or tracking 236 ...Accumulator or up/down counter 138 .Time hopping 237 PULSE NUMBER MODULATION 139 .Chirp 238 PULSE WIDTH MODULATION 140 .Direct sequence 239 PULSE POSITION, FREQUENCY, OR 141 ..End-to-end transmission system SPACING MODULATION 142 ...Having correlation-type 240 BANDWIDTH REDUCTION OR EXPANSION receiver 240.01 .Television or motion video 143 ...Having matched-filter-type signal receiver 240.02 ..Adaptive 144 ...Having multi-receiver or 240.03 ...Quantization interference cancellation 240.04 ....Feed forward 145 ...Having specific signaling for 240.05 ....Feed back code synchronization 240.06 ...Feed forward 146 ..Transmitter 240.07 ...Feed back 147 ..Receiver 240.08 ..Feature based 148 ...Multi-receiver or interference 240.09 ...Polygonal approximation cancellation 240.1 ...Separate coders 149 ...Having specific code 240.11 ....Subband coding synchronization 240.12 ..Predictive 150 ...Correlation-type receiver 240.13 ...Intra/inter selection 151 ....Having SAW or charge-transfer 240.14 ...Plural device 240.15 ...Bidirectional 152 ...Matched-filter-type receiver 240.16 ...Motion vector 153 ....Having SAW or charge-transfer 240.17 ....Half-pixel refinement device 240.18 ..Transform 211 REPEATERS 240.19 ...Wavelet 212 .Ring or star configuration 240.2 ...Discrete cosine 213 .Testing 240.21 ..Subsampling 214 .Including pulse regeneration or 240.22 ..Vector quantization conversion 240.23 ..Variable length coding 215 ..Phase locked loop 240.24 ..Block coding 216 APPARATUS CONVERTIBLE TO ANALOG 240.25 ..Specific decompression process 217 .Muting circuit and squelch 240.26 ..Associated signal processing 218 EARTH OR WATER MEDIUM 240.27 ...Error detection or correction 219 TRANSCEIVERS 240.28 ...Synchronization 220 .Transmission interface between 240.29 ...Pre/post filtering two stations or terminals 241 .Pulse code modulation 221 .Loopback mode 242 PULSE CODE MODULATION 222 .Modems (data sets) 243 .Correcting or reducing 223 ..Angle modulation quantizing errors 224 TESTING 244 .Differential 225 .Data rate 245 ..Quantizer or inverse quantizer 226 .Phase error or phase jitter 246 ..Length coding 227 .Signal noise 247 ..Single bit (delta) December 2011 375 - 2 CLASS 375 PULSE OR DIGITAL COMMUNICATIONS 248 ...Nonamplitude delta (area, 292 .Disparity reduction etc.) 293 .Synchronized 249 ...Compand (overload prevention) 294 ..Phase locked loop 250 ....Redundancy removal 295 TRANSMITTERS 251 ....Syllabic 296 .Antinoise or distortion 252 ...Plural feedback loops (includes predistortion) 253 .Length coding 297 ..Power amplifier 254 .Noise or distortion reduction 298 .Quadrature amplitude modulation 256 PULSE TRANSMISSION VIA RADIATED 299 .Plural diversity BASEBAND 300 .Amplitude modulation 257 CABLE SYSTEMS AND COMPONENTS 301 ..Single or vestigial sideband or 258 .Transformer coupling suppressed carrier 259 SYSTEMS USING ALTERNATING OR 302 .Angle modulation PULSATING CURRENT 303 ..Frequency shift keying 260 .Plural channels for transmission 304 ...Antenna tuning with frequency of a single pulse train shift 261 ..Quadrature amplitude modulation 305 ...Minimum shift keying 262 ...Maximum likelihood decoder or 306 ...One oscillator viterbi decoder 307 ...Two or more oscillators 263 ...Partial response 308 ..Phase shift keying 264 ...Multilevel 309 .Keying circuits 265 ...Trellis encoder or Trellis 310 ..Remote controlled decoder 311 ..Automatic 267 ..Diversity 312 ..Power or bias voltage supply 268 .Amplitude modulation keying 269 ..With phase or frequency shift 313 ..Key shock or click prevention keying 314 ..Including auxiliary control 270 ..Vestigial or single sideband or tube suppressed carrier 315 ..Modulation by absorption of 271 .Angle modulation signal, changing antenna 272 ..Frequency shift keying dimension or changing antenna 273 ...Combined with phase shift impedance keying 316 RECEIVERS 274 ...Minimum shift keying 317 .Automatic baseline or threshold 275 ...More than two frequencies adjustment 276 ...One cycle or less per bit 318 ..Differential amplifier 277 ...Vestigial or single sideband, 319 ..Automatic bias circuit for DC or suppressed carrier restoration 278 ...Antinoise or distortion 320 .Amplitude modulation 279 ..Phase shift keying 321 ..Single or vestigial sideband or 280 ...More than two phases suppressed carrier 281 ....Quaternary 322 .Angle modulation 282 ...Biphase (manchester codes) 323 ..Combined phase shift keyed and 283 ...Differential phase shift frequency shift keyed keying (diphase) 324 ..Particular demodulator 284 ...Antinoise or distortion 325 ...Including coherent detector 285 .Antinoise or distortion 326 ...Carrier recovery circuit or 286 MULTILEVEL carrier tracking 287 .With threshold level 327 ...Phase locked loop 288 .Transmission line 328 ...Including switching or gating 289 .Bipolar signal (digital circuits) 290 .Partial response 329 ..Phase shift keying 291 ..Duobinary 330 ...Differential (diphase) Decenber 2011 CLASS 375 PULSE OR DIGITAL COMMUNICATIONS 375 - 3 331 ....More than two phases 368 ...Synchronizer pattern 332 ...Plural phase (>2) recognizers 333 ...Biphase (manchester code) 369 ..Start - stop 334 ..Frequency shift keying 370 ...With asynchronous data 335 ...More than two frequencies 371 .Phase displacement, slip or 336 ...Minimum shift keying jitter correction 337 ...Separate mark and space 372 ..Elastic buffer channels 373 ..Phase locking 338 .Interrupted carrier wave 374 ...With charge pump or up and 339 ..Carrier controlling local down counters generator 375 ...With frequency detector and 340 .Particular pulse demodulator or phase detector detector 376 ...Phase locked loop 341 ..Maximum likelihood decoder or 377 MISCELLANEOUS viterbi decoder 342 ..Locating predetermined portion of pulse 343 ..Correlative or matched filter E-SUBCLASSES 344 .Automatic frequency control 345 .Automatic gain control E-SUBCLASSES The following subclasses beginning with the letter "E"... 346 .Interference or noise reduction The following subclasses beginning with 347 ..Diversity (frequency or time) the letter E are E-subclasses. Each E-sub­ 348 ..Intersymbol interference class corresponds in scope to a classifi­ 349 ..Plural signal paths in receiver cation in a foreign classification system, 350 ..By filtering (e.g., digital) for example, the European Classification system (ECLA). The foreign classification 351 ..Gating, blanking, etc. equivalent to an E-subclass is identified 352 .With electromagnetic relay or in the subclass definition. In addition to solenoid US documents classified in E-subclasses by 353 PULSE AMPLITUDE MODULATION US examiners, documents are regularly 354 SYNCHRONIZERS classified in E-subclasses according to 355 .Synchronizing the sampling time the classification practices of any for­ of digital data eign Offices identified in parentheses at 356 .Network synchronizing more than the end of the title. For example, "(EPO)" two stations at the end of a title indicates both Euro­ 357 .Synchronization failure pean and US patent documents, as classi­ prevention fied by the EPO, are regularly added to 358 .Feedback, receiver to the subclass. E-subclasses may contain transmitter subject matter outside the scope of this 359 .Self-synchronizing signal (self­ class.Consult their definitions, or the clocking codes, etc.) documents themselves to clarify or inter­ 360 ..With transition detector pret titles. 361 ..Manchester code or biphase code 362 .Frequency or phase control using synchronizing signal E1.001 SPREAD SPECTRUM TECHNIQUES IN 363 ..Synchronization bit insertion GENERAL (EPO) into artificially created gaps E1.002 .Using direct sequence modulation 364 ..Synchronization signals with (EPO) unique amplitude, polarity, E1.003 ..With code acquisition (EPO) length, or frequency E1.004 ...Setting of lock conditions, 365 ..Synchronization word e.g., threshold (EPO) 366 ...Plurality of synchronization E1.005 ...Code identification (EPO) words E1.006 ...Multimode search, i.e., using 367 ...Pseudo noise multiple search strategies (EPO) E1.007 ...Using partial detection (EPO) December 2011 375 - 4 CLASS 375 PULSE OR DIGITAL COMMUNICATIONS E1.008 ....Partial correlation (EPO) E1.032 ...The interference being multi E1.009 ....Partial phase search (EPO) path interference, e.g., RAKE E1.01 ...Multistage acquisition (EPO) receivers (EPO) E1.011 ....Multidwell schemes, i.e., E1.033 .Using frequency hopping (EPO) multiple accumulation times E1.034 ..Arrangements for generation of (EPO) hop frequencies (EPO) E1.012 ....Parallel schemes (EPO) E1.035 ..Arrangements for generation of E1.013 ...Setting of search window, hop sequences (EPO) i.e., range of code offsets to E1.036 ..Interference related aspects be searched (EPO) (EPO) E1.014 ...Masking/slewing, i.e., jumping E1.037 ..Arrangements for sequence within the code (EPO) synchronization (EPO) E1.015 ...With increased resolution, E7.001 SYSTEMS FOR THE TRANSMISSION OF i.e., higher than half a chip TELEVISION SIGNALS USING PULSE (EPO) CODE MODULATION (EPO) E1.016 ..Using a code tracking loop, E7.002 .Arrangements for interfacing to e.g.,