JPH04501647A - Noise suppression circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Noise suppression circuit Yu 5 minutes each other The invention relates to the suppression of noise during signal transmission, and more particularly to the suppression of noise during signal transmission, and more particularly to the suppression of noise during signal transmission. background noise suppression to separate speech and speech-like signals from background noise. do.

Lord Lord! amount Various types of background noise can be used to create an audio system designed to primarily carry speech. It accompanies voice in communication systems. Such type of background noise is Even in near-conditioning systems, automobiles, other mechanical equipment, and crowd backgrounds All of these different types of noise include hiss, white noise, and white noise. all have some type of sound that distinguishes them significantly from sounds produced by a single speaker. Demonstrates temporal properties.

Many conventional noise suppression systems have been developed so far. For example, the main purpose is is the removal of channel noise from weak or non-existent radio frequency (RF) carriers. Squelch system, expansion/compression like DBX and DO1by expander/compressor systems, and noise pulse removers of various designs.

For conventional RF squelch systems, examples thereof include U.S. Pat. 660 ．． 765 (Gl a s e r et al.), 4,638,604 (Koe ber) and 4,158,174 (C; Ruenberger et al.). , when useful information is present in the guided audio channel, output that information. closed to transfer to the power line, while in weak signal-to-noise conditions the corresponding Manually or automatically adjust the darkness value so that the gate opens and squelches the output signal. This is usually set. Such an ordinary squelch system is receiving R F times the signal to determine that it has a high signal-to-noise ratio, but Tests the RF multiplied signal content to determine whether it is voice or background noise. do not. In contrast, the present invention determines what is the content of the obtained audio signal. to suppress background noise while leaving the audio signal.

For expander/compressor systems like DBX or Dolb) systems, Emphasis is placed on examining and adjusting the relative amplitudes of different components of an audio signal. , the final goal is to reduce background noise. In such a system, Distinguishing between sustained sounds, such as long drum beats, and transitional sounds, such as spoken words. On the other hand, the present invention can detect sustained and non-persistent sounds, and repeated drum hits can be However, it is aimed at distinguishing spoken words so that they can be separated as desired signals. It will be done.

In prior art noise pulse remover structures, the statistics of a given waveform are Attempts have been made to examine whether the Ru. However, the nature of the analysis performed in the noise pulse remover is This is very different from the nature of the analysis carried out in China. Noise burst remover is fast Although designed to eliminate long-lasting burst type signals, the present invention Designed to eliminate noise. There is inevitably a difference in emphasis on achieving the desired result. Still other types of prior art knowledge make a difference in the methods and equipment employed to In the noise suppression system, a variation of the conventional RF squelch system is used, In it, the audio signal is analyzed and the sound is heard in a voice communication system. A distinction is made between persistent and non-persistent. U.S. Patent No. 4,461,025 (Fr. In this type of noise suppression system exemplified by , an audio signal that contains both background noise and speech information is separated into 20 so as to obtain short-time power spectra with different energy time lengths. It is integrated over a period of ~100 ms. When audio information appears in this audio signal The power spectrum obtained during the period contains periods of zero or near zero energy, but The power spectrum obtained when only background noise appears in the audio signal is It contains few, if any, such zero energy levels. This distinction Generates a control signal that exists only when only audio components are present in the audio signal used as such.

This control signal is applied to a signal amplifier that receives the audio signal as a second input signal. added.

The multiplier output signal will be zero if either of its two input signals is absent. . Therefore, during the time when only the background signal appears in the audio signal, the multiplier output signal is On the other hand, an audio signal that contains background noise has no audio information in it. is amplified while it appears. The present invention provides a method for detecting the background noise part of an audio signal. differs from the above in that it is removed rather than being amplified along with the audio part of the signal. Separated.

From the foregoing, the present invention provides a signal transmission system, in particular audio parameters, e.g. The amplitudes of various parts are extracted and e.g. System that is later reconfigured in the device and voice transmission data rate reduction system It is recognized that the intention is to suppress background noise. Probably. For convenience, the present invention describes a sound transmission system used in pot implants for ionized hearing persons. Although described with respect to noise suppression in the stem, the present invention is not limited thereto. However, it can also be applied to other signal transmission systems and other devices.

Many people have ionized hearing, the reason for their hearing loss is the conversion of acoustic signals into nerve impulses. Absence or damage of hair cells in the pot. These people therefore No matter how loud the sound is, it is impossible to generate nerve stimulation from sound in a normal manner. For those who cannot benefit from regular hearing aids.

Pot-in-plant system directs electrical stimulation to acoustic nerve fibers leading to sound perception in the brain By doing so, we seek to bypass these hair cells. achieve this purpose A number of methods have been described in the past for The most effective of these One of them is a Crosby entitled “Pot Inplant System for Hearing Prosthesis.” No. 4,532,930 to et al. Said Cr.

The subject matter of the sby et al. patent is incorporated herein by reference.

The Crosby et al. patent describes an electrode array containing multiple platinum ring electrodes in a silicone carrier. A pot-in-plant system is described in which the ear is inplanted in the pot of the ear. The electrode array is a semiconductor integrated circuit. connected to a multi-channel receiver/stimulator unit including channels and other components. The unit is implanted into the patient adjacent to the ear. The receiver/stimulator unit by a tuned coil via an inductive link with an external audio processor that can be worn by and receive data information and power. The voice processor is an erasable program Arranged or programmed to emit data from read-only memory (EFROM) Contains an integrated circuit and various components. EjROM is a patient and Each patient's electrical stimulation perception determined by testing his implanted stimulator/electrode. programmed to suit. This test is performed by the interface unit. Diagnostics and Programming Unit (DPU) connected to the voice processor ).

Crosby et al.'s system includes voiced, voiceless preglottal, and prosody information. various audio programs, including amplitude compression of dominant spectral peaks and audio pinches. Allows the use of processing strategies. The voice processing strategy employed is based on known elaborations. Based on divine physical phenomena and through the use of diagnostic and programming units is tailored to each individual patient. Biphasic pulses in various operating modes The various combinations of electrodes are supplied by switch-controlled current sinks. day The transmission of data depends on the chosen electrode, electrode mode shape, stimulation current, and amplitude burst period. by a series of separate data verses representing the amplitude determined by the interval.

A problem that recipients of inplants often have is that background noise is irritating and unnecessary. The goal is to generate the necessary stimulation. Inplant patients with impaired sound processing ability have positive Like regular listeners, such stimuli are easily filtered out or ignored from background noise. Can not do it.

In the past, when the signal level increased, the audio processor was turned on and then the signal level increased. Use an activation switch to turn off the processor when the level drops. An attempt was made to solve this problem. However, how much is this has the effect that the first note of is lost. In addition, the sudden on/off switch of the signal Ching is distracting and irritating to the endoplant recipient. Also, composite The residual noise in the audio signal is provided to the endoplant recipient along with the audio information therein. .

Main view skin summer brother In accordance with one aspect of the present invention, a slowly varying residual noise level component and a rapidly varying residual noise level component are combined. Suppressing residual noise in processing complex input signals with data components that fluctuate A method is provided. The method includes adding residual noise from the composite signal to the composite input signal. It virtually cancels the noise level component and has a predetermined polarity. to provide an output signal substantially corresponding to the rapidly varying data component of said input signal. applying a slowly varying signal to provide the signal and sensing the output signal. Toto, Providing means for ensuring that said output signal maintains said predetermined polarity. Including providing.

According to another aspect of the invention, a composite having a residual noise level component and a data component. receives an input signal, cancels the noise level component, and sets a predetermined polarity. and noise suppression to provide a unipolar output signal substantially corresponding to the data components. A pressure system is provided. The system is first means for providing a signal corresponding to a value of the residual noise level component; From the signal, derive the unipolar output signal corresponding to the data component of the human input signal. a second means for subtracting said composite input signal to provide; ensuring that the unipolar output signal maintains the predetermined polarity; and third means responsive to said unipolar signal.

According to still another aspect of the invention, there is a low frequency residual noise level component and a high frequency residual noise level component. A noise suppression system is provided that receives an input signal having a wavenumber data component.

The system circuit provides a voltage corresponding to the residual noise level of the input signal. a first means for inputting such a voltage to an output signal corresponding to the data component of the input signal; voltage of the input signal or its equivalent voltage to provide the voltage of the input signal. 2, by limiting the value of the provided voltage so that this voltage To prevent the voltage from exceeding the voltage value of the noise level part or its equivalent. and third means responsive to and coupled to the first means.

According to yet another aspect of the invention, a plurality of the above noise suppression circuits is provided.

In this case, the input signal is separated into several different frequency band channels, and each The channel is equipped with an independent noise reduction circuit. In addition, various noise reduction circuits and the voltage corresponding to the voltage of each noise level component. 1 facilitates selective reduction of noise in different frequency band channels. give different response times.

Wataru Sarasa H1 Hoshidome Other objects, features and advantages of the invention will be apparent from the following detailed description in conjunction with the drawings. It will become clear when. In the drawings, FIG. 1 shows a diagram according to an embodiment of the present invention. FIG. 2 is a circuit diagram of a noise suppression system.

Figure 2 is a graph showing the input signal level plotted against time for the circuit of Figure 1. It is f.

Figure 3 is a graph of capacitor voltage plotted against time for the circuit of Figure 1. It is.

Figure 4 is a graph of the output signal level plotted against time for the circuit in Figure 1. be.

FIG. 5 is a circuit diagram of a noise suppression system according to a second embodiment of the invention.

FIG. 6 shows a digital implementation of a noise suppression system according to another embodiment of the invention. It is a flowchart.

FIG. 7 shows that multiple noise suppression circuits with different response times are connected to a corresponding number of frequency bands. to selectively reduce the noise level in the input signal separated into two channels. FIG. 2 is a block diagram of one embodiment of the present invention that may be employed.

Kishu ■ 1 Noh for disaster - Referring to FIG. It is shown in An input signal, generally designated 10, passes through conductor 11 to system 1. applied. The input signal 10 contains a slowly varying residual noise level component. and a signal with rapidly varying data components. The input signal 10 is, for example, The rectification that occurred in the aforementioned Crosby et al. U.S. Pat. No. 4,532,930 It can consist of an audio signal.

The input signal 10 is connected to one of the inputs of a subtraction device 125, for example a summing amplifier. tree Capacitor 14 is slowly charged by current source 13 connected in series to it. , and provides a second voltage to the subtractor 12, the difference between the two inputs being on line 16. is provided as the output signal level parameter 15 above.

Line 16 passes through line 17 to one input of a converter 182, e.g. an operational amplifier. terminal, and other input terminals are grounded.

Converter 18 serves to sense when output signal 15 is about to go negative.

The output of converter 18 is routed through line 19 to its source and drain terminals. applied to a field effect transistor 20 connected across the capacitor 14. It will be done. Therefore, if the output signal level parameter 15 tries to go negative, the voltage The field effect transistor 20 remains capacitive until the output signal harameter 15 becomes positive again. It operates to discharge the battery 14.

In operation, if there is constant background noise in the input signal 10, Capacitor 14 discharges to the background noise level and its voltage is equal to or lower than input signal 10. In fact, the voltage will be subtracted from the Source 13. Capacitor 14 and subtraction device 12 remove the residual noise level from the input. to add a slowly varying negative signal to the input signal 10 to substantially eliminate the Similarly, the controller constitutes means coupled to the input part of the noise suppression system of the serves as a means for sensing output signal level parameters to the balater 18, and The field effect transistor 20 prevents the output signal from becoming more negative. , the sensitivity of the negative value of the output signal to rapidly add a positive signal to the signal being processed. It serves as a means of responding to knowledge.

A graph showing the input signal level plotted against time for the circuit shown in Figure 1. Referring to Figure 2, we can see that not the signal itself, but the signal energy, envelope, and average A parameter that represents an input signal expressed in the form of a value or other measurement of signal level is a Rise and fall when receiving voice. Between words 40 and 41, the parameter The data does not fall to zero, but to plateau 42, which represents the residual noise level or noise floor. descend. Similarly, between words 41 and 42 the parameters go to noise floor 44. descend. Audio signal energy fluctuates rapidly over tens or hundreds of milliseconds. However, for example, background noise from fans, air conditioners or cars can last for tens of seconds. It changes more slowly. The noise suppression system in Figure 1 is based on signal level parameters. Remove slowly varying noise energy from the data and remove more rapidly varying noise energy from the Leaves the ingredients.

Referring to Figure 3 in conjunction with Figures 1, 2, and 4, after startup, the capacitor The voltage charge on the terminal 14 increases slowly with time as shown at 51. Probably. This charging voltage is caused by a noise filter represented by plateau 42 (Figure 2). input signal 1 until the lower is effectively removed as shown at 42a in FIG. Subtracted from 0. Thereafter, the voltage charge on capacitor 14 becomes 52 in FIG. continues substantially constant as shown by , and in the case of word 41 as shown by 52a rises slightly between words and falls again at the end of the word as shown at 52b. , and the noise floor is until a change occurs in the residual noise bell of the input signal lO, It continues at substantially zero level as shown at 44a in FIG. remove noise level This allows the patient to receive little or no stimulation when the audio portion of the signal stops. I can't.

If the residual noise level of the input signal is reduced to 46 in Figure 2 due to, for example, a fan being If the noise level floor decreases as shown by This will have the effect of forcing field effect transistor 2o negative. Then, a part of the voltage of the capacitor 14 is discharged as shown at 53 in FIG. A new virtually constant low voltage charge is then applied to the capacitor as shown at 54. Appears on the 14th. This new lower constant voltage reduces the residual noise level corresponds to the new noise floor plateau 46 (Fig. 2) caused by The output signal level floor returns to substantially zero level as shown at 46a in Figure 4. do. Therefore, this noise suppression system 1 is adapted to reduce the residual noise level. , and provide the lowest signal level output (noise floor plateau 46) above the dark value stimulus. Adjust to the patient's threshold.

The time constant for charging capacitor 14 is preferably about 2 seconds or less. It lasts about 10 seconds. The effect of short-term constant use, for example about 2 seconds, is Noise is to be removed quickly. However, persistent signals are also removed. to remove background noise for a long period of time, for example about 10 seconds. will take longer. However, such a long period of constant will not affect the sustained signal much. As will be explained in detail later, Figure 1 The system I consists of multiple electrodes, each provided with a different frequency band portion of the input signal. When used in pot inplant systems using Used for high frequency band parts whose character is temporary, and the sound remains constant for long periods of time. Preferably, the layer is used for sustained low frequency parts. The time constant mentioned above The range of 2 to 10 seconds should not be interpreted as absolute. Constant time outside this range This is because it operates to a varying degree.

Referring now to FIG. 5, the present invention employs a Seida diode network. An alternative embodiment 2 of the noise suppression system is illustrated generally as 2. This ingredient In the example, input signal 3o is connected to operational amplifier 32 through capacitor 31. The other input of amplifier 32 is grounded. Output of capacitor 31 is also connected to one side of resistor 33, and the other end is connected to ground. Operational amplifier 3 2 is passed through a diode 34 to an output line 35 of the noise suppression system 2. connected, and the output signal level parameter 36 determines the operating temperature of the system. It appears at the downstream end of channel 35.

Resistor 33 brings the residual noise level floor to virtually zero, so the system acts to slowly and continuously reduce the positive output level of the This corresponds to the functions of current source 13 and capacitor 14 in the specific example of FIG. On the other hand, Operational amplifier 32 and diode 34 are connected if output signal level parameter 36 If it tries to fall below zero, it acts to clamp the output. Output signal level If the voltage level 36 attempts to fall below zero, the capacitor 31 is connected to the amplifier 32 and The diode 34 charges the signal output level parameter to a positive value. Recover. Amplifier 32 and diode 18 therefore function at this point. This corresponds to the converter 18 and field effect transistor 20 in FIG.

The circuitry of the noise suppression system in Figures 1 and 5 is based on the noise suppression system, rather than the signal itself. signal expressed in terms of energy, envelope or average value, or other measure of signal level It should be noted that it operates with slowly changing parameters representing the level.

These systems work equally well regardless of the signal level measurements employed. . This system determines whether a signal has a certain level and frequency (or frequency band) A type of audio processing, e.g. a vocoder, that is analyzed and reconstructed in minutes. Useful in cases such as hearing aids and pot implants. In the case of an inplant in a pot, the following As previously instructed, the signal is analyzed into its parameters and delivered to the patient in the form of electrical stimulation. provided to. Again, as previously instructed, the noise suppression system is is applied independently to many frequency bands, so the noise spectrum is uniform. Even if not, different noise plateaus at different frequencies can still be accurately subtracted. can.

Referring to FIG. 6, a digital embodiment of a noise suppression system according to the present invention is shown. A flowchart is shown generally as 3.

The starting point for this flowchart is shown at 60. This is a conventional initialization step , while the associated microprocessor (not shown) starts the system. It is initialized when the After initialization, the noise suppression algorithm at 61 Command the system to sample the composite input signal level as shown . It then increments the noise floor level as shown at 62 and at 63 Determine whether the noise floor level is greater than the composite signal input level as shown in Set. If the noise floor level is greater than the signal level as shown in 64. For example, the noise floor level is reduced to be equal to the signal level as shown in 65. will be made to suffer. The noise floor level is reduced equal to the signal level as shown in 65. or when the decision made at 63 as shown at 66 is the noise floor The level must be greater than the signal level, the composite signal level minus the noise floor. An output signal equal to the level signal is generated as shown at 67. The algorithm is At 61, the composite input signal level is again sampled as shown at 68. and repeat itself at a high rate while the system is running.

Referring now to Figure 7, in order to provide multiple output signals in different frequency bands, The noise suppression system is shown as 4 in total. As previously instructed, Multifrequency systems for use in whorled endophytes for ionized hearing patients are known. That's it An example of a system is “a multi-frequency system for enhancing auditory stimulation, etc. No. 4,184,856 to Hochmair et al. The Hochmair et al. patent discloses that multiple carrier signals are transmitted in an audio frequency band. A system is disclosed that is modulated by a pulse corresponding to a signal. carrier signal is transmitted receiver with separate channels for receiving and demodulating the signal - transmitted to. The detected pulses are sent to electrodes on the prosthetic device implanted into the pot. applied, such that the electrode stimulates an area with a desired frequency response; placed inside the pot. The pulse has a frequency that corresponds to the frequency of the signal in the audible band. and has a pulse width corresponding to the amplitude of the signal in the audible band. Hochma The disclosure of the ir et al. patent is incorporated herein by reference.

As shown in FIG. 6, the input signal 70 has a total of 71.72, 73. is applied to each of the plurality of channels shown in . Each of channels 71-75 , so that only a limited frequency band portion of the input signal is allowed to pass through. It includes therein corresponding means for filtering the input signal. For this reason, The channel 71 converts the part of the input signal with a frequency between 300 and io OOHz. It includes a filter means 71a designed to pass the filter. Channel 72] , a filter designed to pass a portion of the input signal with a frequency greater than or equal to 000Hz. It includes filter means 72a. Channel 73 is 2000 to 2800 A filter designed to pass a portion of the input signal having a frequency between Hz It includes means 73a. Channel 74 is between 2800 and 4000Hz a filter means 74a designed to pass an input signal having a frequency of ing. Channel 75 has an input frequency between 4000 and 8000& A filter means 75a is provided which is designed to pass a portion of the force signal.

Similarly, each of channels 71-75 corresponds to the corresponding channel in channels 71-75. Rectifying the frequency band portion of the input signal 70 that has passed through the filter means 71a to 75a have the means to do so. The various rectifying means are 71b, 721), 73b, 74b and 75b. The rectifying means 71b to 75b are each The filter means 71a to 75a are connected in series.

Each of channels 71-75 also receives the various rectified input signals within the channel. corresponding means for canceling the residual noise level component from the . in this way, Channel 71 is equipped with residual noise level canceling means or noise suppressor 71c. , the channel 72 is equipped with a residual noise level canceling means or a noise suppressor 72c. Well, the channel 73 has a residual noise level canceling means or a noise suppressor 73c. In addition, the channel 74 is equipped with a residual noise level canceling means or noise suppression H14c. The channel 75 is equipped with a residual noise level canceling means or a noise suppressor 75. Equipped with c. The various noise suppressors 710-75c have their corresponding filters connected in series with the means 713-75a and their corresponding rectifying means 71b-75b; Continued.

Noise suppressors 71c to 75c preferably include the noise suppressors shown in FIGS. 1 and 5, respectively. This includes either of the noise suppression systems 1 and 2. Furthermore, various noise suppression circuits 7 The time constant or response time from 1c to 75c is 2 as previously indicated. in the range between seconds and 10 seconds, and for the reasons given earlier, the higher frequency bands Channels have short time constant, lower frequency band channels are long It is desirable to have time.

From the above discussion, it can be concluded that the improved noise suppression system described here It is understood that residual noise in the signal is removed without affecting the delivery of data. Will. Furthermore, such noise suppression systems can reduce the residual noise level or rapidly compensates for changes in the noise floor and therefore helps people with hearing damage or hearing loss. It is particularly useful for use in equipment used to assist. Furthermore, the present invention , the reduction of the noise component of the input signal in different frequency bands of many input signals simultaneously An improved noise suppression circuit is provided which can be implemented independently.

While specific embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that the broad aspects of the invention It is obvious that various other changes and modifications are possible without departing from the scope of the invention. and, therefore, the claims encompass all such changes and modifications as to the true spirit of the invention. It is covered as belonging to God and scope.

For example, for residual noise suppression the output from the system is generally referred to herein as It is referred to as a positive signal, and monitoring and corrective measures rely on it. The output signal is described as remaining positive.

The frame of reference is inverted so that the output signal is negative with respect to the reference and the corresponding In an embodiment of the invention, the corrective means are used to maintain the output progress negative with respect to the reference. Examples are also expected to be possible.

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Claims (1)

[Claims] 1. The slowly fluctuating residual noise level component and the rapidly fluctuating data component are A system for suppressing residual noise in processing an input signal contained in the system, the system comprising: an input and output unit for receiving said input signal and outputting its data components; a first means comprising a circuit having a circuit having a noise level from the input signal to the residual noise level; substantially canceling the bell component and the rapidly varying data component of the input signal. a slowly varying negative input signal to said input signal so as to provide a substantially equivalent output signal. second means continuous to said input portion of said first means for applying a signal of and, third means for sensing said output signal, said output signal becoming more negative; In order to prevent fourth means responsive to sensing a negative value in the recorded output signal; The system characterized in that it comprises: 2. The input signal includes a rectified audio signal and a low frequency noise component. 2. The residual noise suppression system of claim 1, comprising: 3. The second means includes a resistor connected between the input portion and ground. 4. The residual noise suppression system according to claim 2. The second means includes a current source and a capacitor connected in series with the input portion of the circuit; one input and the other input connected to the midpoint between the current source and the capacitor. 3. The residual noise suppression system of claim 2 including a subtraction device having a power. 5. The third means receives a first input connected to ground and the output signal. The remainder of claim 2 including an operational amplifier having a second input connected to Noise suppression system. 6. The third means includes a grounded input to the output portion of the circuit and a grounded input to the output portion of the circuit. The residual noise suppressor of claim 2 including a comparator having another input connected thereto. pressure system. 7. The fourth means is between the third means and the output portion of the first means. 3. The residual noise suppression system of claim 2 including a diode connected to. 8. Said fourth means are responsive to said third means and in parallel with said second means. selectively sharpening the negative DC output signal sensed by the third means connected to the 3. The residual noise suppression system of claim 2, further comprising gating means for rapidly reducing residual noise. 9. The slowly fluctuating residual noise level component and the rapidly fluctuating data component are A method for suppressing residual noise in processing an input signal having a substantially canceling the residual noise level component from the input signal; and said to provide an output signal substantially corresponding to the rapidly varying data components of said adding a slowly varying negative signal to the input signal; sensing the output signal; A negative output signal is sensed to prevent the output signal from becoming more negative. Adding a rapidly varying positive signal to the signal being processed The method characterized in that it comprises: 10. The rapidly fluctuating positive signal is a fluctuating negative signal applied to the input signal. added to the signal being processed by selectively and rapidly reducing the level of The residual noise suppression method according to claim 9. 11. The slowly varying residual noise level component and the rapidly varying data component are A method for suppressing residual noise in processing an input signal having a substantially canceling the residual noise level component from the input signal; and said to provide an output signal substantially corresponding to the rapidly varying data components of said adding a slowly varying negative signal to the input signal; sensing the output signal; When a negative output signal is sensed, a The method further comprises the step of reducing the varying negative signal. 12. receiving an input signal having a residual noise level component and a data component therein; canceling said noise level component and producing an output signal substantially corresponding to said data component; A noise suppression system for providing a signal, the noise suppression system comprising: first means for providing a signal corresponding to the residual noise level component; the input signal to provide an output signal corresponding to the data component of the input signal; second means for subtracting said signal from a signal; To prevent the signal from exceeding the value of the residual noise level component of the input signal. on said output signal for limiting the value of the signal provided by said first means; third means responsive and coupled to said third means; The system characterized in that it comprises: 13. The input signal includes a rectified audio signal, and the data component is auditory. The first means includes a capacitor and a current connected in series with each other. a current source, and the second means connects the current source and the capacitor in a circuit. one of its inputs connected to an intermediate point and connected to receive said input signal. a subtractor having another input, said third means being within the circuit. and one of its inputs connected to the output of said subtraction device and connected in the circuit. a comparator having another input connected to ground, said third means further comprising gate means controlled by the output of the parameter; is used to selectively discharge the capacitor when the output of the subtraction device becomes negative. 13. The noise suppression system of claim 12, wherein the noise suppression system is connected across the capacitor. 14. The subtraction device includes a summing amplifier, and the comparator includes an operational amplifier. and the gating means includes a gate connected in the circuit to the output of the comparator. and its source and drain connecting it across said capacitor. 14. The noise suppression system of claim 13, comprising a field effect transistor having a field effect transistor. stem. 15. (i) Multi-frequency having residual noise level components and data components therein (ii) each of the output signals contains data in its frequency band; to provide multiple output signals substantially corresponding to the components in different frequency bands. It is a noise suppression system for a plurality of parallel channels for receiving the multi-frequency input signal; A limited frequency band portion passes through filter means in each of said channels. of said channel for filtering said input signal to allow filter means in each of the channels to filter the input signal passed through each of the channels. The frequency band portion is the frequency band portion of the other passed input signal of the channel. and a filter means substantially different from the filter means in said channel. rectifier in each of said channels for rectifying the frequency band portion of the input signal flow means and The output signal in each of said channels is substantially phase-dependent with the data component of the input signal therein. The residual noise level from the various rectified input signals in the channel as per Elimination means in each of said channels for erasing the components. The device characterized in that it comprises: 16. The input signal includes an audio signal, the data component of which increases auditory intelligence. 16. The noise suppression system of claim 15, comprising: 17. Each of said means for canceling said residual noise level component first means for providing a signal corresponding to the value of the level component; said input signal to provide an output signal corresponding to said data component of said input signal. a second means for subtracting said signal from a residual noise of the input signal; provided by the first means to prevent the value of the noise level component from exceeding the value of the responsive to said output signal and coupled to said first means for limiting the value of said output signal; The third means 17. The noise suppression system of claim 16, comprising: 18. The first means includes a capacitor and a current source connected in series with each other. In this case, the second means connects the current source to the intermediate point between the current source and the capacitor in the circuit. one of its inputs connected and the other connected to receive said input signal. a subtraction device having an input of providing said output corresponding to an intelligent part, said third means providing said output corresponding to an intelligent part; one of its inputs connected to the output of the computing device and connected to ground within the circuit. the third means includes a comparator having another input input to the comparator; further comprising gating means controlled by the output of said subtracting the capacitor for selectively discharging the capacitor when the output of the device is negative; 18. The noise suppression system of claim 17, wherein the noise suppression system is connected across the seater. 19. The subtraction device includes a summing amplifier, and the comparator includes an operational amplifier. and the gating means includes a gate connected in the circuit to the output of the comparator. and its source and drain connecting it across said capacitor. 14. The noise suppression system of claim 13, comprising a field effect transistor having a field effect transistor. stem. 20. The residual noise level component includes a slowly varying signal and is minutes contain rapidly fluctuating components, and steps are taken to eliminate the residual noise level components. Each of the stages has an input for receiving said input signal and outputting its data components. and a first means comprising a circuit having an output portion; substantially canceling residual noise level components and the rapidly varying components of the input signal. slowly into said input signal so as to provide an output signal substantially corresponding to the data component. continuous to said input portion of said first means for applying a varying negative signal; a second means, third means for sensing said output signal, said output signal becoming more negative; In order to prevent fourth means responsive to sensing a negative value in the recorded output signal; 17. The noise suppression system of claim 16, comprising: 21. The second means includes a resistor connected between the input portion and ground. 21. The noise suppression system of claim 20. 22. The second means includes a current source, a capacitor connected in series thereto, and a current source connected in series with the current source. one input connected to said input portion of said circuit and said current source and said key. Claims containing a subtraction device having another input connected to the intermediate point of the capacitor Item 20. Residual Noise Suppression System. 23. The third means receives a first input connected to ground and the output signal. claim 20, further comprising an operational amplifier having a second input connected to communicate with the operational amplifier. noise suppression system. 24. The third means includes a grounded input and a grounded input to the output portion of the circuit. 21. The noise suppressor of claim 20, including a comparator having another input connected to the noise suppressor. pressure system. 25. The fourth means includes the third means and the output portion of the first means. 21. The noise suppression system of claim 20 including a diode connected therebetween. 26. Said fourth means are responsive to said third means and in parallel with said second means. selectively rapidly detecting the negative output signal sensed by said third means connected to 21. The noise suppression system of claim 20, including gating means for reducing. 27. said second means adds said slowly varying negative signal to said input signal; rate so as to provide selective suppression of residual noise in different channels. 21. The noise suppression system of claim 20, wherein the noise suppression system is selectively different from each other in the plurality of channels. Tem. 28. The slowly varying residual noise level component and the rapidly varying data component are A method for suppressing residual noise in processing a composite input signal having a substantially canceling the residual noise level component from the composite signal and predetermined substantially corresponds to the rapidly varying data component of said input signal. adding a slowly varying signal to the composite input signal to provide an output signal that sensing the output signal; ensuring that the output signal maintains the predetermined polarity; The method characterized in that it comprises: 29. receives a composite input signal having a residual noise level component and a data component; and has a predetermined polarity and has a predetermined polarity. noise suppression system to provide a unipolar output signal that substantially corresponds to the a first signal for providing a signal corresponding to the value of the residual noise level component; means and providing the unipolar output signal corresponding to the data component of the input signal; third means for subtracting the signal from the composite input signal; in response to the unipolar output signal, the unipolar output signal having the predetermined polarity; The front is characterized by comprising a third means for ensuring that the system.