Abstract: An apparatus and method for detecting the closure of one of several switches using a single input line of a detector is disclosed. The input line is also used to carry an audio-frequency signal when a recording switch is closed. The switches are connected to a network of resistors that cooperate with a pull-up resistor to form a voltage divider. The pull-up resistor is connected to the input line. The switches are closed to selectively switch resistors in the network out of the voltage divider to change the voltage on the input line. A detector reads the voltage on the input line and compares it with a set of predetermined values to determine which switch is closed. If a recording switch is closed, a microphone connected to the network of resistors converts sound to an audio-frequency signal onto the input line.

Abstract: An audio chip with switchable audio output pathways that can be connected to an external circuit board comprises: an operational amplifier, a first output end, a second output end, a means for connection switch, and a status register. An audio signal is outputted to the external circuit board via a first output end of the audio chip. The operational amplifier receives the audio signal that, after amplification, is outputted to the external circuit board via a second output end of the audio chip. According to the connection configuration of the first and second outputs of the audio chip with respect to the external circuit board, an operator can adequately switch the means for connection switch so that a plurality of sound adjusters can control the audio signal delivered by the audio chip.

Abstract: A data processing system comprises an audio processing means receiving data within said data processing system for converting the data into an analog signal with a first and a second analog channel components; an audio output means receiving the analog signal and providing a first and second output signal wherein the first output signal is provided for a loudspeaker and the output second signal is provided for a headset. The control of the audio processing means by a control signal providing an audio signal on the first or on the second channel or on both.

Abstract: A mute apparatus comprises a plurality of mute switches 7 each operative to assume two operation states consisting of a mute-on state and a mute-off state; a mute executing switch 6 operative to assume two executing states consisting of a mute-on state and a mute-off state; mute switch control data generating means 3 for generating mute switch control data elements indicative of the operation states of the respective mute switches 7; mute switch control data determining means 4 for determining whether a mute executing switch 6 is to assume the mute-on or mute-off state on the basis of the mute switch control data elements; and mute switch means 5 for having the mute executing switch 6 selectively assume the mute-on and mute-off states on the basis of the mute-on or mute-off state determined by the mute switch control data determining means 4, thereby making it possible for the single mute switch means 5 to determine the execution state of the mute executing switch 6 to mute or unmute an audio signal inputted

Abstract: The method and apparatus are provided for several audio signal processing apparatuses to share at least one audio output device. Several audio signals sent from the audio signal processing apparatuses are received. The DC levels of the audio signals are shifted to a predetermined value. One of the adjusted audio signals is then selected for signal-transmitting to the audio output device. Afterwards, the DC level of the selected audio signal is re-adjusted to the predetermined value.

Abstract: A terminal connection device is adapted for connecting two voice coils in a speaker between a series connection and a parallel connection wherein the terminal connection device includes a jumper housing and a terminal switch detachably mount thereto. The jumper housing includes a jumper circuit defining a plurality of jumper inlets adapted for electrically connecting with electric outputs of the voice coils respectively and a plurality of jumper terminals electrically extended from the jumper inlets respectively. The terminals switch includes a terminal circuit electrically connected with the jumper terminals of the jumper circuit for selectively switching the voice coils between a series connection and a parallel connection.

Abstract: An audio system and circuit are disclosed that are operable in either a first configuration and a second configuration. The first configuration includes sound processing circuitry, a primary connector, and a header. The second configuration adds an optional secondary connector to the header. The system and circuit mutes or turns off the audio signal at the primary connector and the main output contacts (if any) upon insertion of a plug into the secondary connector in the second configuration. The system and circuit also optionally mutes or turns off the audio signal at a main output contact upon insertion of a plug into the primary connector in each of the first and second configurations. The system may also employ logic switches or FETs to interrupt the audio signal upon insertion of a plug into the secondary connector. The system uses a simple switchless interconnection between the secondary circuit and the main system.

Abstract: The present creation is to provide a switching circuit built in IC for earphone and loudspeaker of portable information device, and there is no any passive component outside the IC, thus making the circuit board assembly more easily, saving the area of the circuit board, decreasing the volume and the cost. It is very suitable in designing a compact portable information device. In order to avoid any possible logic error during the switching between earphone and loudspeaker, the present creation provides a special unsymmetrical design in differential MOS circuit, and provides a current mirror circuit.

Abstract: An integrated device is used to test the tone quality of a plurality of microphones. The device comprises a main body, and a control panel which is mounted on the main body and is provided with a plurality of receiving holes and switches corresponding in location to the receiving holes. The microphones are held in the receiving holes. The switches are used to control the sound pick-up effect of the microphones.

Abstract: A dual-mode transmission device is provided for use with a radio device configured for either push-to-talk operation or voice-operated operation. The dual-mode transmission device includes a mode selecting apparatus that may be switched between a first position in which a push-to-talk mode is enabled and a second position in which the push-to-talk mode is disabled, allowing a single headset or similar device to be used in either mode.

Abstract: For reducing the power consumption of a hearing aid system, an internal or external hearing aid signal source with a signal line for the transmission of a signal to a hearing aid amplifier and a control device for the connection and disconnection of the hearing aid signal source is provided in the hearing aid. A monitoring logic monitors the signal line and supplies a switch signal to the control device, so that the hearing aid signal source can be connected and disconnected on the basis of the switch signal. Each signal source can thus be individually connected and disconnected without employing additional connections from the hearing aid system to the signal source.

Abstract: A deep bass sound booster device comprises a high-pass filter to which an input sound signal is fed and which permits only a frequency component higher than a predetermined frequency to pass through so as to output a resulting signal, a bass booster to which the input sound signal is fed and which amplifies only a frequency component lower than the predetermined frequency and attenuates another frequency component so as to output a resulting signal, a switch to which the signal output from the bass booster is fed at one end and which, when turned on, outputs that signal at another end, and an adder to which the signal output from the high-pass filter is fed and to which the signal output from the switch is fed, the adder adding together those two signals and outputting a resulting signal.

Abstract: Sound control circuit comprising a game port, installed on a digital audiovisual reproduction system managed by an operating system, characterized in that the game port in the sound control circuit is used to create an access to the configuration of the audiovisual reproduction system and/or additional management functions for the audiovisual reproduction system.

Abstract: A method and an apparatus for controlling a sound function of a computer system based on whether or not a headphone plug is inserted into a monitor is disclosed. A switching section receives a sound signal from a main body of the computer system and outputs the sound signal to a speaker or to an inserted headphone plug based on whether or not the headphone plug is inserted by a user. A signal detecting section detects an insertion voltage signal by monitoring an insertion of the headphone plug from the switching section. A control section compares the insertion voltage signal from the signal detecting section with a predetermined reference voltage signal, and controls a speaker installed in the main body according to the compared result. Accordingly, the user can enjoy sound, such as music, regardless of the time.

Abstract: An amplification circuit is provided for the signal output from a microphone in which the signal is amplified by a differential structure amplifier. The circuit includes the pull-up voltage, which initializes the operating state of the microphone, being coupled to a first input of the differential structure amplifier and to a second input of the differential structure amplifier through a pull-up resistor.

Abstract: A sound mixing control console used in live concert performances, etc., includes a master control section having motorized knobs for controlling variable parameters such as input gain, pan, frequency equalization and the like of individual input channels. Each of plural input channels includes a dedicated fader for controlling output level and a selector switch for applying the master control section to that channel for controlling other variable parameters besides output level. A memory subsystem stores and recalls the positions of the motorized knobs. When an input channel is selected, the knobs of the master control section assume positions corresponding to the current values of the variable parameters, which may then be adjusted manually and stored. Signal processing is carried out by digitally-controlled circuitry.

Abstract: An in-the-ear hearing aid having multiple directional microphones connected to a signal processing unit. The connection of the microphones can be reversed by a selector switch to selectively switch the hearing aid between a left-ear configuration and a right-ear configuration.

Abstract: An acoustic countertop display comprises a housing adapted to sit on a countertop and a controller mounted within the housing. The controller stores a plurality of prerecorded sounds. The housing further includes a plurality of input devices mounted on a surface of the housing. The input devices are in communication with the controller, and each input device is associated with one of the plurality of prerecorded sounds. A speaker is mounted within the housing and is in communication with the controller. Actuation of one of the plurality of input devices by a user orders the controller to send one of the prerecorded sounds associated with the actuated input device to the speaker. The speaker then emits the prerecorded sound to the user.

Abstract: Provided is a method (500) and audio circuit (100) for reducing popping noise in a load (140, 145) connected to the audio circuit, especially during audio circuit start-up. The method applies a time varying voltage (364) to the load that has a smooth, S-shaped curve when plotted over time. The device include an integrated circuit (IC) set as a channel block (110), a load connected between the channel block and ground, a bypass control (150) connected to the channel block for producing a controlled ground reference voltage having an S-shaped curve to the channel block, a shunt control (170) controlling the voltage delivered across the load, and a ground capacitor (160) coupled between the bypass control and ground. The channel block typically includes an amplifier which supplies the output voltage across the load. The bypass circuit generally includes a bypass generator and a transistor selectively providing a charge to the ground capacitor.

Abstract: The present invention has all the properties and capabilities of a standard direct-box, which is an audio adapter circuit in a rugged chassis. It allows high-impedance stereo headphones to be connected. It comes equipped with a switch that turns the signal to the exterior sound system on/off without interrupting sound to the headphones. The present invention also comes with a locking cover, which prevents inadvertent operation of additional switches, such as a ground lift switch or attenuation level switch. The cover also functions as a mounting structure.

Abstract: A communication/control device according to the invention may include a housing, a discrete switch and a membrane switch. The discrete switch and the membrane switch may be enclosed in the housing. The discrete switch may be in communication with a life-safety device. The membrane switch may be in communication with an environment device. In a method according to the invention, a housing is provided that has therein a discrete switch in communication with a life-safety device and a membrane switch in communication with an environment device. One of the switches may then be actuated to communicate information.

Abstract: An audio processing system for used in a multi-channel audio chip includes a multiplexer, a digital-to-analog converter, a de-multiplexer, a controller and N sample-and-hold circuits. The multiplexer receives N digital signals and outputs the digital signals one by one in a time-division manner. The digital-to-analog converter receives the digital signals from the multiplexer and converts them into corresponding N analog signals. The de-multiplexer outputs the analog signals one by one in a time-division manner. The controller generates control signals to control the selection of the multiplexer and the de-multiplexer. The sample-and-hold circuits hold the analog signals for a predetermined period of time and then outputs the signals, respectively.

Abstract: A system and method are provided for sensing a sound system. In one embodiment, a sound card or other such device is provided that includes an analog audio output system and a digital audio output system. Both the analog and digital audio output systems are coupled to a common audio output port through which either an analog or digital sound system is driven. The common audio output port provides a first line out and a second line out that may be employed to transmit the right and left channels of a stereo analog audio signal. Alternatively, one of the first and second line outs may be employed to transmit a digital audio signal, where the remaining line out is coupled to ground. Only one of the analog and digital output systems are enabled to transmit sound through the common audio output port to the respective sound system at a time. Accordingly, the present system and method are provided to determine whether an analog or digital sound system is coupled to the common audio output port.

Abstract: The programmable analog input/output integrated circuit system includes a plurality of integrated circuit pins, an analog input/output circuit, a control module, and a switching module. The analog input/output circuit is coupled to the plurality of pins and determines the input/output status of each of the pins. The control module generates an I/O control signal and a switching control signal based on the input/output status of the integrated circuit pins. The I/O control signal is provided to the analog I/O circuit, which configures itself as an input or output based on the I/O control signal. The control module provides the switching control signal to the switching module, which configures itself to couple the analog input and/or analog output to corresponding functional circuitry of the corresponding integrated circuit.

Abstract: A portable computer system includes an audio circuit and a common audio input socket coupled to the audio circuit. This audio circuit has a controller and two amplifiers. Two types of external audio devices is to be coupled to the common audio input socket. The controller controls the two amplifiers alternately depending upon the audio type of the external audio device coupled to the common audio input socket. In a preferred embodiment, a first amplifier is provided for amplifying stereo audio signals and a second amplifier for amplifying a mono audio signal. When the controller detects a mono audio device, the microcontroller disables the first amplifier. Detecting a stereo audio device, the controller disables the second amplifier.

Abstract: An improved hearing aid is disclosed having a switched release automatic gain control. In one embodiment, an input signal is presented to a comparator with a reference typically around, for example, 65 dB SPL instantaneous. The output of the comparator controls a switch in a release circuit of an automatic gain control. While the instantaneous input level exceeds the threshold, the release circuit is enabled and the automatic gain control behaves normally. While the instantaneous input level does not exceed the threshold, the release circuit is disabled and the automatic gain control maintains its current gain setting, essentially indefinitely. Because speech, even soft speech, has a very high positive peak content, this circuit will recover any needed gain in the presence of speech (assuming an appropriate threshold) but not recover gain to background noise whose positive peak content is below the threshold.

Abstract: In a first mode where no audio reproduction is to be executed in a second zone, each selector switch shifts to a Z1 contact. In a second mode where audio reproduction is to be executed in the second zone, each selector switch shifts to a Z2 contact. In the second mode, a DSP executes sound field correction on main and rear signals such that sound fields in the first zone have desired characteristics. Setting section can select either a first speaker mode where speakers connected to first output terminals and speakers connected to second output terminals are both positioned in the first zone, or a second speaker mode where the speakers connected to the first output terminals are positioned in the first zone and the speakers connected to the second output terminals are positioned in the second zone. When the output to the first output terminals is off while the output to the second output terminals is on in the second speaker mode, the DSP stops outputting the surround signals.

Abstract: A test signal generator (10) outputs a test signal which is obtained by cutting off a high-frequency component from a white noise signal. A signal switching device (18) selectively outputs either one of a positive-phase signal of the test signal and a negative-phase signal of the test signal, in response to a switching operation of the user. A selector (16) selectively outputs either one of the test signal and a musical sound signal to speaker terminals (26, 28). The test signal is reproduced while the selector (16) is connected to the test signal side. At this time, the test signal is output as it is from one channel. A signal which is obtained by selectively outputting either one of the positive-phase signal of the test signal and the negative-phase signal of the test signal is reproduced from the other channel. If, when the test signal is positive-phase, the sound is localized between the left and right loudspeakers, the connection polarities of the left and right loudspeakers is attained.

Abstract: A microphone assembly comprising; a transducer for receiving acoustic waves through a sound inlet port, and for converting received acoustic waves to analog audio signals, a pre-amplifier having an input and an output terminal, the input terminal being connected to the transducer so as to receive analog audio signals from the transducer, switching means having one or more input terminals, and an output terminal, a first input terminal of the one or more input terminals being connected to the output terminal of the pre-amplifier so as to receive amplified analog audio signals from the pre-amplifier, and an analog-to-digital converter having an input and an input/output terminal, the input terminal being connected to the output terminal of the switching means so as to convert received analog audio signals to digital audio signals. Preferably the switching means is configured so as to be controlled by a characteristic of a received auxiliary analog audio signal, such as its DC level or its AC amplitude level.

Abstract: A device to audibly verify the activation of a solid state relay. The device includes an audio output device that is coupled to the solid state relay to produce a sound when the solid state relay is activated. The sound produced by the audio output devices emulates the sound of an electromechanical relay when switched.

Abstract: There is provided an acoustic sound reproducing apparatus for a first audio signal and having an input terminal for receiving a second audio signal, a selector switch and at least one loudspeaker. The at least one loudspeaker is driven by an output signal from one of the first or second audio signal through the selector switch. As a result, the acoustic sound reproducing apparatus, and the apparatus providing the second audio signal, can commonly use a single loudspeaker or set of loudspeakers. When the external audio signal is selected, the internal loudspeaker(s) becomes part of the external loudspeaker arrangement for a surround sound system. When more than one loudspeaker is used, the loudspeakers are connected to each other in series when they are connected to be driven by the external second audio input signal instead of each being driven by their respective amplifiers.

Abstract: A method and apparatus for automatically compensating a sound volume are disclosed. The method includes the steps of determining whether a channel conversion key and an audio input switching key are inputted, producing an energy of an audio signal when the channel conversion key is inputted, and comparing an energy value of the audio signal detected for a predetermined time period with an energy value obtained from a previous step thereof and compensating for as much volume as a difference obtained by the comparison. The method together with the apparatus considers a symmetrical characteristic of an audio signal, calculates a voice energy with regard to a half signal of the audio signal, converts the calculated signal to a simplified value, and automatically compensates for the volume accordingly, thereby removing redundant manual steps.

Abstract: A circuit, which is enabling the superpositioning of different audio signals such as voice, music or ringer signals in a audio output device is achieved. The individual superpositioning can be activated and performed by a combination of resistors and switches without the need of an additional mixing amplifier as in prior art. One common output stage is used for all the signals activated and superpositioned. The adjustment of the amplitude of the output signal, which can be used for the volume adjustment of a loudspeaker, is provided by a precise amplitude setting via the gain control stages of an inverting voltage amplifier through a current-voltage conversion. Said current-voltage conversion is performed by a string of resistors activated by a string of correspondent switches. This circuit reduces the power consumption, the chip area required and the offset and improves the power supply rejection rate (PSSR).

Abstract: A guitar amplifier having at least one channel, each channel having a differential amplifier with first and second amplifying members, each amplifying member having a control element, an electron emitting element and an electron collecting element, the electron emitting elements of the amplifying members commonly coupled and an output amplifier coupled to the differential amplifier and having an output terminal selectively coupled to the control element of the second amplifying member of the differential amplifier as a feedback path. An input terminal coupled to the control element of the first amplifying member and a user-adjustable presence control circuit selectively coupled between the control element of the first amplifying member and ground to increase the perceived brightness, when selected. The presence control circuit includes a high pass filter disposed between the input terminal and ground to filter a selected high frequency portion of the signal received at the input terminal.

Abstract: A mute circuit for momentarily inhibiting signal travel in the signal path having an input terminal and an output terminal in response to operation of a coil-operated relay. The signal path will preferably include a plurality of channel in parallel. A plurality of switch responsive coil-operated relays are disposed in the signal path with a separate unidirectional signal path coupling each of the coils of each of the coil-operated relays to a muting line with the coil of each said relay providing a signal on the muting line responsive to collapse of the magnetic field developed in the relay coil by the flow of current therethrough. A plurality of time controlled switching devices are responsive to a signal on the muting line from a coil to momentarily inhibit signal travel in the signal path. The timing circuit is included in the time controlled switching device to control the length of operation of the switch in response to a signal on the muting circuit.

Abstract: An electronic control that monitors the switching means used to operate transducers to detect conditions that can cause improper transducer operation. In the application the unenergized state of the transducer is always safe. Should a switch in the transducer circuitry be in an erroneous state, the control uses another switch to prevent improper operation of the transducer without requiring the involvement of the operator. Monitoring enables the control to prevent transducer operation before failures allow hazardous operation. Any switching means, activated by the control, an override, or both may be monitored as long as its intended state is known to the control. The control can also open the transducer circuitry when an externally controlled switch in the transducer circuitry changes state at a destructive rate.

Abstract: The sound quality regulation apparatus has one attenuation unit and one amplification unit connected in series in this order in the signal line of the apparatus. The output of the attenuation unit is fed to a multiplicity of sound regulators associated with the split frequency bands of the input signal. Each sound regulator includes a switched capacity filter and a selector for selectively supplying the output of the sound regulator to either the attenuation unit, amplification unit, or none of these units. The sound quality regulation apparatus is thus capable of individually attenuating, enhancing, or not changing split frequency bands of the input signal.

Abstract: A sound field forming circuit includes a first switch portion which switchingly supplies one of an audio signals from a sound source and a second tone control circuit which variably adjusts a characteristic of a second predetermined frequency band, to a first tone control circuit which variably adjusts a characteristic of a first predetermined frequency band; a second switch portion which switchingly supplies one of the audio signals from the sound source and the first tone control circuit, to the second tone control circuit; a third switch portion which switchingly supplies one of the audio signals from the first tone control circuit and the second tone control circuit, to a front channel; and a fourth switch portion which switchingly supplies one of the audio signals from the first tone control circuit and the second tone control circuit, to a rear channel.

Abstract: An apparatus and method for controlling the audio noise attenuation by monitoring a buffer are disclosed. If the audio data to be reproduced, and if the user sets the operation as an automatic mode so that the operation of controlling the audio noise attenuation by monitoring the buffer is automatically executed, the operation of the loudspeaker is interrupted. In addition, if the audio data to be reproduced is stored, the loudspeaker is continuously driven regardless of the set of the mode. Furthermore, if there is no the audio data to be reproduced, and if the operation is not set as the automatic mode, the loudspeaker is operated. Accordingly, the analog noise, which may be generated when silence is outputted from the loudspeaker, can be eliminated, thereby improving the quality of the conference and the audio reproducing quality.

Abstract: A hands-free switch device for a wireless intercom includes a signal reception circuit, a sensor, a voice transmission detecting circuit, a manual switch, a determining and controlling unit circuit, a reception/emission switching circuit, a microphone, an earphone, and a speaker. The sensor is adapted for wearing on the user's neck or other parts of the user's body that vibrates when the user speakers. The determining and controlling unit circuit is coupled to the signal reception detecting circuit, the voice transmission detecting circuit and the reception/emission switching circuit such that, when the voice control function is activated, a control signal is generated according to the states of the signal reception detecting circuit and the voice transmission detecting circuit.

Abstract: A background-sound control apparatus, a background-sound control method, readable recording medium containing a background-sound control program, and a video game apparatus improve effectiveness of background-sound data provided over a predetermined number of channels. When background sounds are produced through a speaker, a sound-level controller controls output ratios for sound levels defined in background-sound data on a channel basis and uses a sound-level control function to perform crossfading sound-level control.

Abstract: A reception apparatus or transmission and reception apparatus has a plurality of input terminals, and a plurality of apparatus are connected by a chain connection to a predetermined one of the input terminals. The input terminal at which the apparatus is to receive a signal is successively switched among the input terminals by selection operation of a user, and the apparatus connected to the predetermined input terminal are successively searched in response to the same selection operation of the user.

Abstract: An integrated device is used to test the tone quality of a plurality of microphones. The device comprises a main body, and a control panel which is mounted on the main body and is provided with a plurality of receiving holes and switches corresponding in location to the receiving holes. The microphones are held in the receiving holes. The switches are used to control the sound pick-up effect of the microphones.

Abstract: The present invention relates to an audio amplifier using a pulse width modulation, and more particularly, to a pulse width modulation type audio amplifier which an average switching frequency or a cutoff frequency of a low pass filter is variable in accordance with frequency of input signal.

Abstract: In an active noise control method of the present invention, a noise detection signal from a noise referring microphone which detects ambient noise is inputted into noise processing units of different types to produce noise silencing signals. A selected noise silencing signal is inputted into a receiver or a speaker together with a reception signal via an adder, so that a regenerated tone from the noise silencing signal silences the ambient noise, When a nonconformance detecting unit judges that the selected noise silencing signal exceeds a predetermined range, the corresponding noise processing unit is judged to be incompatible, and a switch control unit controls a switch to select another one of the noise processing units.

Abstract: So as to shape the spatial amplification characteristic of an acoustical to electrical converter arrangement at least two sub-arrangements (I, II) of converters are provided, generating different spatial amplification characteristics. Frequency domain converted signals ({tilde over (S)}1) which are proportional to the output signals of the sub-arrangement are compared in a unit (39) on respective spectral frequencies (fs) and there is generated at the output of the comparing unit (39) a binary spectral comparison result signal (A39). Signals ({tilde over (S)}2) which are as well proportional to the output signals of the sub-arrangements (I, II) are fed to a switching unit (41). For each spectral frequency (fB) the control signal from unit 39, as a binary spectral signal, controls the spectral amplitude of which of the two input signals ({tilde over (S)}2) is passed to the output (A41) of the switching unit and of the arrangement.

Abstract: A multi-accessory vehicle audio system is providing that includes a plurality of vehicle audio accessories, the vehicle audio accessories generating a corresponding plurality of audio signals; and an audio switching device. The audio switching device includes an input section for receiving the audio signals from the vehicle audio accessories, a switching section operatively coupled to the input section for receiving the audio signals, a controller operatively coupled to the input section for receiving the audio signals and operatively coupled to the switching section for providing control signals to control the switching section and to regulate the output of the audio signals from the switching section according to an instruction set, and an output section operatively coupled to the switching section for receiving the regulated audio signals outputted from the switching section.

Abstract: A high performance audio processing device having significantly increased reconfigurability capabilities and that offers far more precision and throughput than its predecessors without increasing the per-channel cost of the device above the per-channel cost of the predecessors. The device architecture includes a single-cycle, 48×28 bit multiply feature that is configured as a sophisticated switch to minimize the use of branching such that the reconfiguration capabilities of the device are significantly increased. Multiplying by zero shuts a path off, while multiplying by one turns the path on, and multiplying by −1 turns the path on, but with an inversion of the path signal's phase. The use of a full-precision multiply rather than other forms of decision logic also allows “morphing” from one setting to another on-the-fly, and provides new operating states that are linear combinations of the “on” and “off” settings.

Abstract: An electret microphone circuit including an electret microphone having a field effect transistor (FET) with a gate coupled to an electret diaphragm, a drain coupled to provide audio frequency output to an audio output node, a source terminal coupled to ground, and an amplifier stage with an RLC circuit coupled to the drain for configuring the audio frequency output to desired characteristics and for obtaining microphone bias from the output node. The amplifier stage can comprise discrete transistors or integrated operational amplifiers. In another embodiment of the invention there is provided a transistor with a drain coupled to provide audio frequency output to an audio output node and for obtaining microphone bias am from said output node, a source terminal coupled to the microphone housing, and an NPN transistor current mirror stage with an RC or RLC circuit coupled to the source for configuring the audio frequency output to desired characteristics.

Abstract: A sound card and related method includes a sound processing circuit, a rear primary connector, and a switching connector header coupled therebetween. The switching header includes a normally closed spring contact that opens in response to insertion of a plug in the header. Upon opening of the connector header switches, the audio signal is received by a secondary connector coupled to the plug and disposed at the front of a computer. The secondary connector has a normally closed switch that enables the signal to pass back to the header and to the primary connector. Each of the primary connector and secondary connector may be auto-muting to interrupt the audio signal at a main output contact in response to insertion of a headphone or other jack therein. The sound card is operational either with or without the secondary connector.