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Class Number: 381
Class Title: ELECTRICAL AUDIO SIGNAL PROCESSING SYSTEMS AND DEVICES
Subclass Subclass
Number Title
1 BINAURAL AND STEREOPHONIC
2 .Broadcast or multiplex stereo
3 ..FM final modulation
4 ...AM subcarrier
5 ....Four discrete channels
6 .....Having transmitter
7 ....Switch-type detector or modulator
8 .....Two diodes
9 .....Four or more diodes
10 ....Channel seperation control
11 ....Automatic switchover between mono and stereo modes
12 ....Stereo indicators (e.g., stereo presence)
13 ....Antinoise
14 ....Having transmitter
15 ..AM or both AM and angle final modulation
16 ...Having transmitter
17 .Pseudo stereophonic
18 ..Pseudo quadrasonic
19 .Quadrasonic
20 ..Matrix
21 ...4-2-4
22 ....Variable decoder
23 ....With encoder
23.1 .Hearing aid
24 .Speaker arrangement
25 ..Earphone
26 .Stereo sound pickup device (microphone)
27 .Center channel
28 .Amplifier
29 AUDIO BANDWIDTH COMPRESSION OR EXPANSION
30 .With content reduction encoding
33 .Delay line
34 TIME COMPRESSION OR EXPANSION (E.G., RUN LENGTH CODING)
35 .With content reduction encoding
36 SPEECH ANALYSIS AND SYNTHESIS COMBINED
37 .Using frequency
38 ..Pitch
39 ..Formants
40 .Using time
41 SPEECH ANALYSIS (E.G., PHONEME RECOGNITION)
42 .Voice recognition
43 .Word recognition
44 ..Phonetic typewriters
45 ..Frequency domain
46 .Detection of speech in noise
47 .Signal to noise ratio enhancement
48 .Speech parameter display
49 .Speech pitch fundamental frequency
50 .Speech formant frequencies
51 SPEECH SYNTHESIS
52 .Speech from printed matter
53 .Vocal tract modell
54 HELIUM SPEECH
55 AUDIO TRANSDUCER PROTECTION CIRCUITRY
56 MONITORING OF SOUND
57 .Amplification control responsive to ambient sound
58 MONITORING/MEASURING OF AUDIO DEVICES
59 .Loudspeaker operation
60 .Testing of hearing aids
61 SOUND EFFECTS
62 .Tremelo or vibrato effects
63 .Reverberators
64 ..Mechanical (e.g., reverberation chamber)
65 ...Helical spring
66 DEREVERBERATORS
67 STETHOSCOPES, ELECTRICAL
68 HEARING AIDS, ELECTRICAL
68.1 .Directional
68.2 .Frequency control
68.3 .Bone conduction
68.4 .Gain control
68.5 .Spectacle
68.6 .Ear insert
68.7 .Hook over ear
69 .Specified casing or housing
69.1 ..Having vacuum tube amplifier
69.2 ..Having battery
70 ARTIFICIAL LARYNX, ELECTRICAL
71 ACOUSTICAL NOISE OR SOUND CANCELLATION
72 HEARING PROTECTORS, ELECTRICAL
73.1 SOUND OR NOISE MASKING
74 HEADPHONE CIRCUITS
75 MEGAPHONES
76 LECTERNS
77 ONE-WAY AUDIO SIGNAL PROGRAM DISTRIBUTION
78 .Drive-in
79 .Near field
80 .Multiple channel
81 ..With switching
82 .Public address system
83 ..Feedback suppression
84 ..Spare amplifier substitution
85 ..Speaker or channel switching
86 VEHICLE
87 HAVING NON-ELECTRICAL FEATURE (E.G., MOUNTING)
88 .Having enclosure or housing
89 ..With loudspeakers driven in given phase relationship
90 ..With loudspeaker (e.g., baffle, spatial orientation, etc.)
91 ..With microphone
92 DIRECTIVE CIRCUITS FOR MICROPHONES
93 FEEDBACK SUPPRESSION
94 NOISE SUPPRESSION
95 MICROPHONE FEEDBACK
96 LOUDSPEAKER FEEDBACK
97 INCLUDING PHASE CONTROL
98 INCLUDING FREQUENCY CONTROL
99 .Having crossover filter
100 ..With active device
101 .Automatic tone control
102 ..With amplitude controll
103 .Having automatic equalizer circuit
104 INCLUDING AMPLITUDE OR VOLUME CONTROL
105 .Remote
106 .With amplitude compression/expansion
107 .Automatic
108 ..Including feedback
109 .With manual volume control
110 VOICE CONTROLLED
111 CIRCUITRY COMBINED WITH SPECIFIC TYPE MICROPHONE OR LOUDSPEAKER
112 .With carbon microphone
113 .With electrostatic microphone
114 .With piezoelectric microphone
115 .With magnetic microphone
116 .With electrostatic loudspeaker
117 .With magnetic loudspeaker
118 WITH MUSICAL INSTRUMENT
119 WITH MIXER
120 WITH AMPLIFIER
121 .Feedback
122 HAVING MICROPHONE
123 SWITCHING
150 ELECTRO-ACOUSTIC AUDIO TRANSDUCER
151 .Body contact wave transfer (e.g., bone conduction earphone,
larynx microphone)
152 .Driven diverse static structure (e.g., wall, sounding board)
153 .With acoustic wave modifying structure
154 ..Including sound conducting tube
155 ..Directional
156 ..Sound intensifying or spreading element (e.g., horn)
157 ...Mouthpiece
158 ..Absorbing or attenuating element (e.g., baffle, obstruction,
damping)
159 ..Enclosure or resonant cavity
160 ..Reflecting element
161 .With mechanical amplifier arrangement
162 .Detail of mechanical vibration coupling to transducer (e.g.,
tuned vibrating element)
163 .Having bi-directional transducer
164 .Thermal response to, or generation of, sound vibration
165 .By modifying fluid flow
166 .Having a fluid as a conducting element
167 ..Ionized gap, spark, or flame
168 .Microphone
169 ..With mounting or support feature
170 ..Compound
171 ..Micromagnetic
172 ..Light modifying
173 ..Piezoelectric or ferroelectric
174 ..Capacitive
175 ..Semiconductor junction microphone
176 ..Conductive diaphragm (e.g., reed, ribbon)
177 ..Dynamic (e.g., magnetic)
178 ..Vibrating electrical contract
179 ..Resistive
180 ...Granular or carbon
181 ....Differential
182 .Plural or compound reproducers
183 ..Headphonee
184 ..Different types of diaphragms
185 ..Having common voice coil
186 ..Plural diaphragms
187 .Having body supported structure (e.g., earphone)
188 .With mounting or support feature
189 .Having protective or sheilding feature
190 .Electrostrictive, magnetostrictive, or piezoelectric
191 .Having electrostatic element (e.g., electret, vibrating plate)
192 .Electromagnetic (e.g., dynamic)
193 ..Having feature of edge-supported diaphragm
194 ..Movable voice coil
195 ...Multiple (e.g., double)
196 ...Pattern
197 ...Centering
198 ..Including adjustment mechanism
199 ..Magnetic circuit or core structure
200 ...Armature
201 ...Magnetic configuration (e.g., tubular or U-shaped)
202 ..Specified diaphragm shape or structure
203 ...Flat
204 ...Conical
205 .Electro-acoustical transducer mounting or support
124 MISCELLANEOUS