Patent EP0410663A2 successfully refreshed from Google Patents.
EP0410663A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
AM noise reducing
Assignee: Bose Corp
•
Filing: 1990-07-23
•
Granted: —
•
Expires: 2010-07-23
Abstract
Abstract A receiver for receiving an amplitude modulated signal with upper and lower sidebands comprises an independent sideband receiver (6) for providing demodulated upper (USB) and lower (LSB) sideband audio signals, a quality detector (9) for providing upper and lower quality signals representative of undesired noise in the demodulated upper and lower sideband audio signals respectively and a selector (11,19,61) responsive to the quality signals for processing the upper and lower sideband audio signals to provide an audio output signal with reduced noise. Examples are described in which a plurality of band-pass filters are provided for decomposing the upper and lower sidebands into several contiguous pass bands, and in which a stereo decoder is used for decoding a stereo signal and detecting a stereo pilot signal.
Inventors
- 👤 Amar G. Bose
- 👤 William R. Short
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 14:58
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/44; H04H20/46; H04H20/47; H04H20/49; H04B; H04B1/00; H04B1/06; H04B1/10; H04B1/1027; H04B1/16; H04B1/30; H04B1/302; H04B2001/1063
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
84 words
A receiver for receiving an amplitude modulated signal with upper and lower sidebands, the receiver comprising: an independent sideband receiver (6) for providing demodulated upper (USB) and lower (LSB) sideband audio signals; a quality detector (9) for providing upper and lower quality signals representative of undesired noise in the demodulated upper and lower sideband audio signals respectively; and, a selector (11,19,61) responsive to the quality signals for processing the upper and lower sideband audio signals to provide an audio output signal with reduced noise.
Claim 2
Dependent Claim
84 words
A receiver for receiving an amplitude modulated signal with upper and lower sidebands, the receiver comprising: an independent sideband receiver (6) for providing demodulated upper (USB) and lower (LSB) sideband audio signals; a quality detector (9) for providing upper and lower quality signals representative of undesired noise in the demodulated upper and lower sideband audio signals respectively; and, a selector (11,19,61) responsive to the quality signals for processing the upper and lower sideband audio signals to provide an audio output signal with reduced noise.
Claim 3
Dependent Claim
25 words
A receiver according to claim 1, wherein the quality detector (9) comprises a prefilter (28,29,39) for each of the upper and lower sideband audio signals.
Claim 4
Dependent Claim
14 words
A receiver according to claim 2, wherein the prefilters are high pass filters (39).
Claim 5
Dependent Claim
18 words
A receiver according to claim 2, wherein the prefilters are 10 kHz high Q band pass filters (28,29).
Claim 6
Dependent Claim
59 words
A receiver according to any of claims 1 to 3, wherein the quality detector (9) comprises a combiner (32) for differentially combining the demodulated upper and lower sideband audio signals to provide a noise signal, and a correlator (33,34,35) for correlating the noise signal and the demodulated sideband audio signal in the associated sideband to provide the quality signals.
Claim 7
Dependent Claim
22 words
A receiver according to claim 5, wherein the quality detector (9) further comprises low pass filters (36,37) for providing the quality signals.
Claim 8
Dependent Claim
47 words
A receiver according to any of claims 1 to 6, further comprising variable band pass filters (44,45) responsive to the quality signals and filtering the demodulated upper and lower sideband audio signals, the selector (11,19) being responsive to the output of the variable band pass filters (44,45).
Claim 9
Dependent Claim
69 words
A receiver according to any of the preceding claims, further comprising a plurality of band-pass filters (59) for selectively transmitting spectral components of the demodulated upper and lower sideband audio signals in contiguous frequency bands, a corresponding plurality of quality detectors (9) and selectors (61) each associated with a respective band pass filter (59), and a summer (62L,62R) for combining the output audio signals provided by the selectors (61).
Claim 10
Dependent Claim
67 words
A receiver according to any of the preceding claims, wherein the or each selector (11,19,61) comprises a plurality of variable gain amplifiers (48,49) for amplifying signals related to the demodulated upper and lower sideband audio signals, and a summer (50,57) for combining the outputs of the variable gain amplifiers (48,49), the variable gain amplifiers each having a gain controlled by control signals related to the quality signals.
Claim 11
Dependent Claim
21 words
A receiver according to claim 9, further comprising a logic device responsive to the quality signals for providing the control signals.
Claim 12
Dependent Claim
22 words
A receiver according to claim 10, further comprising an integrator (39) integrating the control signals for controlling the variable gain amplifiers (48,49).
Claim 13
Dependent Claim
47 words
A receiver according to any of the preceding claims, further comprising a stereo decoder (15) for decoding a stereo signal and detecting a stereo pilot tone, the or each selector (19,61) being additionally responsive to the detected stereo pilot tone for providing left and right stereo signals.
Claim 14
Dependent Claim
24 words
A receiver according to claim 12, wherein the selector (19) further comprises variable gain amplifiers (61L,61R) for selecting the left and right stereo signals.
Claim 15
Dependent Claim
63 words
A receiver according to any of the preceding claims, wherein the selector (11,19) further comprises a summer (51) for summing the demodulated upper and lower sideband audio signals, a low pass filter (52) for filtering the summed upper and lower sideband audio signals, and variable gain amplifiers (48,49) for selecting the summed or the filtered and summed upper and lower sideband audio signals.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.