US4228545A
Expired / Lapsed
US
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Receiver device having a function for suppressing transient noises during abrupt interruptions
Assignee: NTT Inc
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Filing: 1979-04-18
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Granted: 1980-10-14
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Expires: 1999-04-18
Abstract
Abstract A receiver device comprises a demodulator for demodulating speech signals received at an input terminal of the device, a delay memory for storing, with a delay, speech signals of prescribed period for a predetermined time, a detector for detecting an abrupt interruption and its period of the received speech signals, a discriminator for discriminating whether the speech signals stored in the delay memory are periodic or non-periodic, an interpolator for creating interpolating information during the abrupt interruption from the signals stored in the delay memory under the control of the detector by receiving the outputs from the discriminator and the abrupt interruption detector, and a switch which is adapted, under the normal condition, to receive and transmit signals from the demodulator to the output of the device, while it is adapted, under the condition that the abrupt interruption and the period thereof is detected, to select signals from the interpolator and to transmit the selected interpolating signals to the output terminal of the device.
Inventors
- 👤 Hideyo Murakami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:33
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/34; H03G3/345; H04; H04B; H04B1/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
177 words
A receiver device having a function of suppressing noises during abrupt interruptions comprising: a demodulator for demodulating speech signals received at the input terminal of the device; memory means for storing, with a delay, the demodulated speech signals of a prescribed period for a predetermined time; means for detecting an abrupt interruption and its period of the received speech signals; means for discriminating whether the speech signals stored in said delay memory means are periodic or non-periodic; an interpolator for creating interpolating information during the abrupt interruption from signals stored in the delay memory means under the control of said detection means by receiving the outputs from said discriminating means and the abrupt interruption detection means; and switch means which is adapted, under the normal condition, to receive and transmit signals from the demodulator to the output of the device, while it is adapted, under the condition that the abrupt interruption and the period thereof is detected, to select signals from the interpolator and to transmit the selected interpolating signals to the output terminal of the device.
Claim 2
Dependent Claim
177 words
A receiver device having a function of suppressing noises during abrupt interruptions comprising: a demodulator for demodulating speech signals received at the input terminal of the device; memory means for storing, with a delay, the demodulated speech signals of a prescribed period for a predetermined time; means for detecting an abrupt interruption and its period of the received speech signals; means for discriminating whether the speech signals stored in said delay memory means are periodic or non-periodic; an interpolator for creating interpolating information during the abrupt interruption from signals stored in the delay memory means under the control of said detection means by receiving the outputs from said discriminating means and the abrupt interruption detection means; and switch means which is adapted, under the normal condition, to receive and transmit signals from the demodulator to the output of the device, while it is adapted, under the condition that the abrupt interruption and the period thereof is detected, to select signals from the interpolator and to transmit the selected interpolating signals to the output terminal of the device.
Claim 3
Dependent Claim
66 words
A receiver device according to claim 1 wherein a further switch means is provided between the demodulator and the delay memory means, said switch means acting to pass the output from the demodulater when the abrupt interruption detection means does not detect abrupt interruptions, and to send the output from the delay memory means to its input side when said detection means detects an abrupt interruption.
Claim 4
Dependent Claim
57 words
A receiver device according to claim 1 wherein said speech signals for the demodulator are modulated analog speech signals, and wherein there is provided an analog-digital converter between the demodulator and the delay memory means for sampling the output of the demodulator with first clock pulses, and a digital-analog converter between the interpolator and the output terminal.
Claim 5
Dependent Claim
155 words
A receiver device according to claim 3 wherein said delay memory means comprises a first register having a capacity to receive the output from said analog-digital converter and to store a predetermined number of samples, a random access memory means to receive the output from said register, write means for performing a write operation to said first register at a first rate substantially equal to the sampling rate of the analog-digital converter and for transferring the information from said first register to said random access memory means at a high speed second rate not affecting said write operation, and means for cyclicly transferring stored samples from said random access memory means to said discriminating means at a high speed third rate under said normal condition and for sending signals from said random access memory means to said interpolator at said first rate based on the output from the discriminating means when detecting the abrupt interruption.
Claim 6
Dependent Claim
35 words
A receiver device according to claim 1 wherein said speech signals for the demodulator are modulated digital speech signals, and wherein there is provided a digital-analog converter on the output side of the switch means.
Claim 7
Dependent Claim
61 words
A receiver device according to claim 1 wherein said abrupt interruption detection means comprises means for rectifying the received signals, a low pass filter for receiving the output from said rectifier, a comparator for comparing a reference value with the output from said low pass filter, and means for holding the output from said comparator for a predetermined period of time.
Claim 8
Dependent Claim
183 words
A receiver device having a function of suppressing transient noises during abrupt interruptions comprising: means for regenerating and repeating the received speech signals; memory means coupled to said means for regenerating and repeating for storing with a delay, speech signals of prescribed period for a predetermined period of time; means for detecting an abrupt interruption and its period of the received speech signals; means for discriminating whether the speech signals stored in said delay memory means are periodic or non-periodic; an interpolator for creating an interpolating information during the abrupt interruption from the signals stored in the delay memory means under the control of said detection means by receiving the outputs from said discriminating means and the abrupt interruption detection means; and switch means which is adapted, under the normal condition, to receive and transmit signals from the regenerative repeater to the output of the device, while it is adapted, under the condition that the abrupt interruption and the period thereof is detected, to select signals from the interpolator and to transmit the selected interpolating signals to the output terminal of the device.
Claim 9
Dependent Claim
183 words
A receiver device having a function of suppressing transient noises during abrupt interruptions comprising: means for regenerating and repeating the received speech signals; memory means coupled to said means for regenerating and repeating for storing with a delay, speech signals of prescribed period for a predetermined period of time; means for detecting an abrupt interruption and its period of the received speech signals; means for discriminating whether the speech signals stored in said delay memory means are periodic or non-periodic; an interpolator for creating an interpolating information during the abrupt interruption from the signals stored in the delay memory means under the control of said detection means by receiving the outputs from said discriminating means and the abrupt interruption detection means; and switch means which is adapted, under the normal condition, to receive and transmit signals from the regenerative repeater to the output of the device, while it is adapted, under the condition that the abrupt interruption and the period thereof is detected, to select signals from the interpolator and to transmit the selected interpolating signals to the output terminal of the device.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-14 | 1984-04-14 | 1984-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-14 | 1988-04-14 | 1988-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-14 | 1992-04-14 | 1992-10-14 | $7700.00 | Window Closed / Lapsed |