发明名称 |
DYNAMIC NOISE FILTER FOR AN AUDIO SIGNAL IN A TELEVISION |
摘要 |
<p>A dynamic noise filter especially adapted for use in audio reproduction systems within a television display device is provided to eliminate perceived noise. An audio signal having a relatively wide frequency range is passed through a variable bandwidth lowpass filter, the upper frequency cutoff point being variable in response to a control signal. A control path includes a filter and detector circuit for generating the control signal in response to the amplitude of the audio signal within an upper frequency portion of the audio signal frequency range. The control signal controls the bandwidth of the lowpass filter inversely with respect to the level of the audio signal within the upper frequency portion of the frequency range. A further filter is included in the control path for providing substantial attenuation at the fundamental frequency and lower order harmonic frequencies of the television horizontal line scanning signal in order to prevent the control path from erroneously responding to this signal.</p> |
申请公布号 |
CA1209246(A) |
申请公布日期 |
1986.08.05 |
申请号 |
CA19830438696 |
申请日期 |
1983.10.11 |
申请人 |
RCA CORPORATION |
发明人 |
MURPHY, WESLEY W., III;HETTIGER, JAMES |
分类号 |
H03H11/04;H04N5/60;(IPC1-7):H04N5/60 |
主分类号 |
H03H11/04 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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