What follows are the subclasses from one class of the Manual of Classification for US patents. As you scroll through the list and encounter a class/subclass of interest, you can jump back to the top and retrieve patent titles by entering the class/subclass in the box below.
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363-131 121-55A 14-.5
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Class Number: 375
Class Title: PULSE OR DIGITAL COMMUNICATIONS
Subclass Subclass
Number Title
1 SPREAD SPECTRUM
3 REPEATERS
3.1 .Testing
4 .Including pulse regeneration or conversion
5 APPARATUS CONVERTIBLE TO ANALOG
6 EARTH OR WATER MEDIUM
7 TRANSCEIVERS
8 .Modems (data sets)
9 ..Angle modulation
10 TESTING
11 EQUALIZERS
12 .Automatic
13 ..Training period or initial set up
14 ..Adaptive
15 ...Quadrature channels
16 ...Accumulator or up/down counter
17 MULTILEVEL
18 .Partial response
19 .Disparity reduction
20 .Synchronized
21 PULSE NUMBER MODULATION
22 PULSE WIDTH MODULATION
23 PULSE POSITION, FREQUENCY, OR SPACING MODULATION
24 PULSE AMPLITUDE MODULATION
25 PULSE CODE MODULATION
26 .Correcting or reducing quantizing errors
27 .Differential
28 ..Single bit (delta)
29 ...Nonamplitude delta (area, etc.)
30 ...Compand (overload prevention)
31 ....Redundancy Removal
32 ....Syllabic
33 ...Plural feedback loops
34 .Noise or distortion reduction
122 BANDWIDTH REDUCTION OR EXPANSION
35 PULSE TRANSMISSION VIA RADIATED BASEBAND
36 CABLE SYSTEMS AND COMPONENTS
37 SYSTEMS USING ALTERNATING OR PULSATING CURRENT
38 .Plural channels for transmission of a single pulse train
39 ..Quadrature amplitude modulation
40 ..Diversity
41 .Amplitude modulation
42 ..With phase or frequency shift keying
43 ..Vestigial or single sideband or suppressed carrier
44 .Angle modulation
45 ..Frequency shift keying
46 ...Combined with phase shift keying
47 ...Minimum shift keying
48 ...More than two frequencies
49 ...One cycle or less per bit
50 ...Vestigial or single sideband, or suppressed carrier
51 ...Anti-noise or distortionn
52 ..Phase shift keying
53 ...More than two phases
54 ....Quaternary
55 ...Biphase (manchester codes)
56 ...Differential phase shift keying (diphase)
57 ...Antinoise or distortion
58 .Antinoise or distortion
59 TRANSMITTERS
60 .Antinoise or distortion (includes predistortion)
61 .Single or vestigial sideband or suppressed carrier
62 .Frequency shift keying
63 ..Antenna tuning with frequency shift
64 ..Minimum shift keying
65 ..One oscillator
66 ..Two or more oscillators
67 .Phase shift keying
68 .Keying circuits
69 ..Remote controlled
70 ..Automatic
71 ..Power or bias voltage supply keying
72 ..Key shock or click prevention
73 ..Including auxiliary control tube
74 ..Modulation by absorption of signal, changing antenna dimension
or changing antenna impedance
75 RECEIVERS
76 .Automatic baseline or threshold adjustment
77 .Single or vestigial sideband or suppressed carrier
78 .Angle modulation
79 ..Combined phase shift keyed and frequency shift keyed
80 ..Particular demodulator
81 ...Phase locked loop
82 ...Including switching or gating (digital circuits)
83 ..Phase shift keying
84 ...Differential (diphase)
85 ....More than two phases
86 ...Plural phase (>2)
87 ...Biphase (manchester code)
88 ..Frequency shift keying
89 ...More than two frequencies
90 ...Minimum shift keying
91 ...Separate mark and space channels
92 .Interrupted carrier wave
93 ..Carrier controlling local generator
94 .Particular pulse demodulator or detector
95 ..Locating predetermined portion of pulse
96 ..Correlative or matched filter
97 .Automatic frequency control
98 .Automatic gain control
99 .Interference or noise reduction
100 ..Diversity (frequency or time)
101 ..Intersymbol interference
102 ..Plural signal paths in receiver
103 ..By filtering (e.g., digital)
104 ..Gating, blanking, etc.
105 .With elctromagnetic relay or solenoid
106 SYNCHRONIZERS
107 .Network synchronizing more than two stations
108 .Synchronization failure preventionn
109 .Feedback, receiver to transmitter
110 .Self synchronizing signal (self clocking codes, etc.)
111 .Frequency or phase control using synchronizing signal
112 ..Synchronization bit insertion into artificially created gaps
113 ..Synchronization signals with unique amplitude, polarity,
length or frequency
114 ..Synchronization word
115 ...Pseudo noise
116 ...Synchronizer pattern recognizers
117 ..Start - stop
118 .Phase displacement, slip or jitter correction
119 ..Phase locking
120 ...Phase locked loop
121 MISCELLANEOUS