Microelectromechanical microphones typically operate in an audible band of frequencies, and also can operate at ultrasonic frequencies. Analog microelectromechanical microphones can include an electro-acoustic sensor that can convert acoustic signals into an electrical signal, and an amplifier that can amplify the electrical signal. Thus, to permit detection of an ultrasonic signal in an analog microelectromechanical microphone, it can suffice that the electro-acoustic sensor, the amplifier, and an acoustic channel of the analog microelectromechanical microphone have a bandwidth extending into ultrasonic frequencies.
In contrast, digital microelectromechanical microphones include an analog-to-digital (A/D) converter that can convert an analog electric signal into a digital signal. The A/D converter can introduce quantization noise into the digital signal through a noise shaping process in which an amount of quantization in the signal band can be mitigated by pushing the low-frequency noise to high frequencies. As such, in the presence of an ultrasonic signal, a noise shaping range of a digital microelectromechanical microphone may be required to extend to frequencies significantly higher than the audible band of frequencies. Therefore, conventional digital microelectromechanical microphones typically increase a clock frequency of the A/D converter and, optionally, another clock frequency of a device that can format output digital signals. Such an approach can be inefficient in terms of noise shaping and can result in high power consumption because ultrasonic signals are usually narrow-band and, therefore, a large portion of the increase in clock frequency leveraged for noise quantization is not applied to frequencies that carry meaningful information. Further, when a maximum available clock frequency in the circuitry associated with the digital microelectromechanical microphone is limited, signal-to-noise ratio can significantly degrade for high-frequency ultrasonic signals.
The following presents a simplified summary of one or more of the embodiments in order to provide a basic understanding of one or more of the embodiments. This summary is not an extensive overview of the embodiments described herein. It is intended to neither identify key or critical elements of the embodiments nor delineate any scope of embodiments or the claims. Its sole purpose is to present some concepts of the embodiments in a simplified form as a prelude to the more detailed description that is presented later. It will also be appreciated that the detailed description may include additional or alternative embodiments beyond those described in the Summary section.
This disclosure recognizes and addresses, in at least certain embodiments, the issue of detection of ultrasonic signals in microelectromechanical microphones. Detection of ultrasonic signals can be utilized in vehicular applications and/or gesture recognition. In one embodiment, the disclosure can provide a digital microelectromechanical microphone, including an electro-acoustic sensor that can receive an acoustic signal including an ultrasonic signal. The electro-acoustic sensor can generate an electric output signal representative of the acoustic signal. The microelectromechanical microphone also can include an amplifier that can generate a second electric output signal using the first electric output signal. The microelectromechanical microphone can further include a band-pass sigma-delta modulator that can receive the second electric output signal, and can generate a digital output signal representative of the ultrasonic signal. The digital output signal can be generated using the second electric output signal. In addition or in other embodiments, the acoustic signal also can include an audible signal and the amplifier can generate a third electric output signal. The microelectromechanical microphone also can include a low-pass sigma-delta modulator that can generate another digital output signal representative of the audible signal. Such a digital output signal can be generated using the third electric output signal. It can be readily appreciated that such a microelectromechanical microphone can permit independently adjusting, e.g., optimizing, the band-pass sigma-delta modulator for ultrasonic signals and the low-pass sigma-delta modulator for audible signals.
Other embodiments and various examples, scenarios, and implementations are described in more detail below. The following description and the drawings set forth certain illustrative embodiments of the specification. These embodiments are indicative, however, of but a few of the various ways in which the principles of the specification may be employed. Other advantages and novel features of the embodiments described will become apparent from the following detailed description of the specification when considered in conjunction with the drawings.
The disclosure is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of this disclosure. It may be evident, however, that the disclosure may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the disclosure. This disclosure recognizes and addresses, in at least certain embodiments, the issue of detection of ultrasonic signals. Detection of ultrasonic signals can be utilized in vehicular applications and/or gesture recognition. As described in greater detail below, embodiments of the disclosure permit detection of audible and ultrasonic signals is provided by a microelectromechanical microphone. The detection range of ultrasonic signals can be configurable. In certain embodiments, the microelectromechanical microphone can include a band-pass sigma-delta modulator that can generate a digital signal representative of an ultrasonic signal. In addition or in other embodiments, the microelectromechanical microphone can include an event detector device that can determine that an ultrasonic event has occurred and, in response, can send a control signal to an external device. Detection of ultrasonic signals can be utilized in vehicular applications and/or gesture recognition.
With reference to the drawings,
The second electric output signal can be analog, and the microelectromechanical microphone 100 can convert such a signal to a digital signal. To that end, in at least certain embodiments, the microelectromechanical microphone 100 can include a low-pass sigma-delta modulator 130 and a band-pass sigma-delta modulator 140. The low-pass sigma-delta modulator 130 can receive the second electric output signal and can generate a first digital output signal 135 based at least on the second electric output signal. The first digital output signal 135 can be representative or otherwise indicative of an audible signal included in the acoustic signal 106. As such, first digital output signal 135 can be referred to as audio signal 135. In one implementation, the low-pass sigma-delta modulator 130 can embody or can include a single-bit sigma-delta modulator. As depicted in panel 150 in
In addition, the band-pass sigma-delta modulator 140 can receive the second electric output signal, and can generate a second digital output signal 145 based at least on the second electric output signal. The second digital output signal 145 can be representative or otherwise indicative of an ultrasonic signal included in the acoustic signal 106. Therefore, the second digital output signal 145 can be referred to as ultrasonic signal 145. The band-pass sigma-delta modulator 140 can have a specific center frequency and a specific bandwidth, either one or both of which can be configurable or otherwise programmable in order to accommodate various ultrasonic frequencies. The bandwidth can be defined with respect to the center frequency. For example, the center frequency can be at about 58 kHz and the bandwidth can be equal to about 4 kHz. Therefore, in one aspect, the band-pass sigma-delta modulator 140 can reject quantization noise to frequencies outside the bandwidth with respect to the center frequency. The band-pass sigma-delta modulator 140 can be embodied in or can include, for example, a second-order or higher-order sigma-delta modulator. In one implementation, the band-pass sigma-delta modulator 140 can embody or can include a single-bit sigma-delta modulator. In another implementation, the band-pass sigma-delta modulator 140 can embody or can include a multi-bit sigma-delta modulator. In addition or in other implementations, the band-pass sigma-delta modulator 140 can be embodied in or can include a discrete-time sigma-delta modulator or a continuous-time sigma-delta modulator. The band-pass sigma-delta modulator 140 can utilize or otherwise leverage the same or a different clock frequency than that utilized by the low-pass sigma-delta modulator 130 for the audible portion of the acoustic signal 106.
The low-pass sigma-delta modulator 130 can format the audio signal 135 according to one of a pulse density modulation (PDM) format, an inter-IC sound (I2S) controller format, a time division multiplexing (TDM) format, a SoundWire format, a SlimBus format, or any other format suitable for generation of a digital signal that can be consumed by a disparate device. Similarly, the band-pass sigma-delta modulator 140 can format the ultrasonic signal 145 according to one of a PDM format, an I2S controller format, a TDM format, a SoundWire format, a SlimBus format, or any other format for generation of a digital signal.
By fitting or otherwise configuring the microelectromechanical microphone 100 with separate A/D converters that can generate digital signals from analog signals having disparate frequencies, the processing of an audible portion of an acoustic signal can be decoupled from the processing of an ultrasonic portion thereof. Not only can such a decoupling permit accurate processing of the both audible and ultrasonic signals, but in certain embodiments, it also can permit detecting presence of an ultrasonic signal—which can represent, in one example, an ultrasonic event.
Specifically, as an illustration,
The digital output signal generated by the band-pass sigma-delta modulator 240 can be supplied to an event detector (ED) device 250 that can process the digital output signal. The ED device 250 can be embodied in or can include a digital signal processor (DSP) or another type of processor that can apply detection logic configured to determine if an ultrasonic event has occurred. The ultrasonic event can be embodied in or can include, for example, presence or absence of an ultrasonic signal in the acoustic signal 206; presence of an ultrasonic signal having a magnitude that exceeds a certain threshold or having another type of metric that satisfies a specific criterion; presence of an ultrasonic signal having a defined feature and/or pattern of defined features; a combination of the foregoing; or the like. In response to ascertaining that the ultrasonic event is present, the microelectromechanical microphone 200 can generate an interrupt signal that can be output via a pin 280 or another type of output interface. The interrupt signal can be sent to a host device, such as a codec device, a sensor hub, or an application processor (AP).
Decoupling the generation of a digital signal associated with an audible portion of an acoustic signal from the generation of another digital signal associated with an ultrasonic portion of the acoustic signal can afford improved operational flexibility.
Similar to other microphones of this disclosure, digital output signal DA and digital output signal DUS generated in the microelectromechanical microphone 300 can be output via a pin 340 and a pin 350, respectively. Other types of output interfaces also can be configured to output digital output signal DA and/or digital output signal DUS. In addition, the microelectromechanical microphone 400 also includes a pin 418 and a pin 412 that can be utilized, respectively, to provide an electric ground and to configure (e.g., receive or provide or otherwise supply) a defined voltage in the electromechanical microphone 400.
In certain embodiments, the output of digital signals can be multiplexed. Multiplexing can simplify integration of microelectromechanical microphones of this disclosure into other equipment.
The timing signal generated by the frequency multiplier device 420 can be input into a multiplexer device 410 that can multiplex the two-bit stream at a rate commensurate with the frequency g of the timing signal. For instance, the multiplexer device 410 can multiplex the two-bit stream at double the rate of the input clock signal: For f=2.4 MHz, g=4.8 MHz and the rate at which the two-bit stream is multiplexed is about 0.21 μs. As such, the microelectromechanical microphone 400 can output two bits in a single stream: one bit for audio and one bit for ultrasound. The signal generated by the multiplexer device 410 can be output via a pin 430. Other types of output interfaces also can be configured to output digital output signal D. As an example, in a scenario in which the left/right (L/R) select pin 416 of the microphone is tied to a voltage pin Vdd 412, the microelectromechanical microphone 400 can operate on the left channel and the two output bits (audio and ultrasound) can be generated on rising edge of the input clock signal 406. Thus, the two output bits can be separated by a time interval Δτ=(4f)−1, corresponding to a quarter-period of the input clock signal. Diagram 450 in
The multiplexing of digital output signals as described in connection with the example microelectromechanical microphone 400 can be utilized to arrange two microphones in a stereophonic configuration in which the two microphones can share a single data line for communication with a codec device. One of the two microphones can correspond to a first channel (e.g., left (L) channel) and the other can correspond to a second channel (e.g., right (R) channel). The stereophonic configuration is illustrated in diagram 500 in
In certain implementations, the microelectromechanical microphone 502a (which can be referred to as the L-channel microphone) can generate two successive output bits (one audio bit and one ultrasound bit) on a rising edge of the clock signal. In addition, the microelectromechanical microphone 502b (which can be referred to as the R-channel microphone) can generate two successive output bits (one audio and one ultrasound bit) on the falling edge of the clock. To that end, the microelectromechanical microphone 502a can include an electro-acoustic sensor 512a configured to receive a pressure wave, and a voltage source device 510a. The microelectromechanical microphone 502a also can include an amplifier 514a that receives an output signal from the electro-acoustic sensor 512a. In accordance with aspects of this disclosure, the microelectromechanical microphone 502a includes a low-pass sigma-delta modulator 516a and a band-pass sigma-delta modulator 518a. A timing device 520a is coupled to such modulators and can provide a timing signal to each of the low-pass sigma-delta modulator 516a and the band-pass sigma-delta modulator 518a. The timing signal generated by the timing device 520a can be output to a frequency multiplier 524a. For the sake of illustration, the frequency multiplier 524a is shown as an m=2 multiplier and can double the frequency of the timing signal output by the timing device 520a. In accordance with further aspects of this disclosure, the microelectromechanical microphone 502a can include a multiplexer device 522a that can generate a digital output signal as described herein in connection with
Diagram 550 in
It should be appreciated that the stereophonic configuration illustrated in
As described herein, embodiments of this disclosure permit processing both audio and ultrasonic signals with a very small amount of power consumption, thus allowing for always-on mode of operation. In always-on mode, a microelectromechanical microphone in accordance with the disclosure can be operated at a clock frequency v that is lower than clock frequencies utilized in operation after a defined event (ultrasonic or otherwise) is detected. Such an event can cause wake-up of a host device, such as a codec device, after which wake-up high-frequency operation of the microelectromechanical microphone can be implemented. In one example, v can be equal to about 768 kHz. In another example, v can be equal to about 384 kHz. While selection of a value of the clock frequency v can be guided by processing capabilities of the host device, it should be appreciated that most any frequency can be utilized in this disclosure.
With respect to always-on mode, it should be appreciated that the microelectromechanical microphone 600 can be operated in monophonic operation when included in a stereophonic configuration such as the one described in connection with
Stereophonic configurations in accordance with this disclosure (see, e.g.,
As described herein, a digital microelectromechanical microphone in accordance with this disclosure can monitor an environment for an event (ultrasonic or otherwise). Detection of the event can cause the digital microphone to instruct an external device to perform certain action, such as a wake-up process or other type of functionality (actuation of lights or other appliances; transmission of a communication, etc.).
In response to detection of a defined audible event and/or a defined ultrasonic event, the digital microelectromechanical microphone 700 can generate an interrupt signal that can be leverage to wake up a host device 770 (e.g., a codec device, sensor hub, an AP, or the like).
The digital microelectromechanical microphone 700 includes two multiplexers: A data multiplexer device 730 and a control multiplexer device 740. The data multiplexer device 730 can multiplex audio signals and ultrasonic signals generated, respectively, by the low-pass sigma-delta modulator 310 and the band-pass sigma-delta modulator 320. Thus, the multiplexing performed by the data multiplexer device 730 can result in multiplexed data signal, which can be referred to as data-stream signal. The data multiplexer device 730 can send the multiplexed data signal to host device 770 via a pin 750 functionally coupled to a communication line (e.g., a data line) of the host device 770. Other types of output interface besides a pin also can be utilized. Similarly, the control multiplexer device 740 can multiplex interrupt signals generated by the VAD device 710 and the USD device 720. The control multiplexer device 740 can send the multiplexed control signal to host device 770 via a pin 760 functionally coupled to another communication line (e.g., a control line) of the host device 770. Other types of output interface besides a pin also can be utilized. It should be appreciated that, as described herein, other arrangements of the inverter 610 can be implemented. For example, the inverter 610 can be integrated into the timing device 330. For another example, the inverter 610 can be integrated into the low-pass sigma-delta modulator 310. In yet another example, the inverter 610 can be integrated into the data multiplexer device 730 or the multiplexer device 740.
In certain embodiments, the microelectromechanical microphone 700 can include one or more storage devices (referred to as a buffer) in order to buffer audio signal while the VAD device 710 executes or otherwise implements a process to detect a voice event (e.g., presence of a keyword, a phrase, or other types of utterances). Information retained in the buffer can be sent to the host device 770 upon or after the host device is ready to receive data. The buffer can be embodied in or can include one or more first-in-first-out (FIFO) registers, one or more static random-access memories (SRAMs, a combination of the foregoing, or the like.
In certain embodiments, the complexity of the digital microelectromechanical microphone 700 can be reduced while maintaining substantially the same functionality.
In certain embodiments, microelectromechanical microphones in accordance with this disclosure can include a programmable component, which in certain implementations can improve operational flexibility.
The LP/BP sigma-delta modulator 910 can output a digital output signal via a pin 920 or another type of output interface. The specific type of noise shaping—e.g., LP noise shaping or BP noise shaping—that can be implemented by the programmable sigma-delta modulator 910 can be configured in numerous ways. In one embodiment, an input pin 908 can receive information, such as an instruction or other type of programming input signal, indicative of a noise-shaping configuration. In another embodiment, the digital microelectromechanical microphone 900 can include an internal setting that can permit switching controllably between LP noise shaping and BP noise shaping. In certain implementations, the internal setting can be embodied in or can include information (e.g., data, metadata, and/or signaling) retained in a register or other type of or a non-volatile internal memory. In addition or in other implementations, the internal setting can be achieved via digital logic and/or analog switching elements (e.g., a MOSFET) that can suitably reconfigure the LP/BP sigma-delta modulator 910 from a first type of noise shaping to a second type of noise shaping, as illustrated in diagram 1050 of
While in certain embodiments of the disclosure the conversion from an analog signal representative of an acoustic signal received at a microelectromechanical microphone can be performed by a sigma-delta modulator, it should be appreciated that the disclosure is not limited in this respect and A/D conversion and/or encoding can include and/or can be performed by other components. As an illustration,
In certain embodiments, the microelectromechanical microphone 1100 can include one or more components for automatic gain control, offset cancellation, frequency equalization, and/or non-linearity cancellation. In a scenario in which one of the analog low-pass sigma-delta modulator 1105a or the analog band-pass sigma-delta modulator 1105b can be configured to generate directly PDM output as intended, only one of the signal paths (either audio or ultrasonic) can require additional processing for generation of the PDM output signal 1160. For example, U.S. patent application Ser. No. 14/719,507, filed on May 22, 2015 and assigned to the Assignee of the present disclosure, discloses various example of the additional processing that may be implemented for generation of the PDM output signal 1160. The contents of such patent application are hereby incorporated by reference herein in their entirety.
As described herein, a microelectromechanical microphone of the disclosure can include circuitry to generate a digital output signal (including separate audio signal and ultrasonic signal, for example) according to a format suitable for a digital signal, such as I2S format, TDM, format, SoundWire format, or SlimBus format. Such audio and ultrasonic signals can be time-multiplexed in the microelectromechanical microphone using one of such protocols, and subsequently demultiplexed by a host device in order to generate an audio bit-stream and an ultrasonic bit-stream.
The audio signal that is output from the LP filter device 1250 is internal to the host device 1200 and can be sent to other portions thereof (components, processors, sensors, devices, etc.) for further processing by the host device 1200. The US signal output from the mixer device 1270 also is internal to the host device 1200 and can be sent to other portions thereof (components, processors, sensors, devices, etc.) for further processing by the host device 1200.
As described herein, two microelectromechanical microphones in accordance with this disclosure can generate a digital output signal in a stereophonic configuration.
In addition or in other embodiments, the ultrasonic path can additionally include one or more mixer devices to down-convert the ultrasonic signal to a baseband frequency. As illustrated in the example input stage 1310 of the host device 1310, a mixer device 1390a can receive a digital output signal from the BP filter device 1380a and can mix it with a reference signal at the baseband frequency, resulting in a digital signal that is internal to the host device 1300 and can be output to other portions thereof (components, processors, sensors, devices, etc.) for further processing by the host device 1300. In addition, a mixer device 1390b can receive a digital output signal from the BP filter device 1380b and can mix it with another reference signal at the baseband frequency, resulting in another digital signal that also is internal to the host device 1300 and can be output to other portions thereof (components, processors, sensors, devices, etc.) for further processing by the host device 1300.
Conventional audio codec devices can include only low-pass analog-to-digital converters in order to process audio, or audio and ultrasonic signals.
A digital output of the band-pass filter device 1460 can be input into a mixer device 1470, resulting in a second digital output signal representative of an ultrasonic signal present in the acoustic signal. The first digital output signal and the second digital output signal also can be processed at a processor 1480 (e.g., a DSP or other types of dedicated hardware) utilizing digital signal processing techniques, for example. It should be appreciated that, in certain embodiments, the codec device 1400 also can include additional components as part of the audio path and/or the ultrasonic path, for DC offset cancellation, automatic gain control, noise gating, and the like. In addition or in other embodiments, the codec device 1400 also can include additional circuitry and/or control components in order to reconfigure each of the audio path and the ultrasonic path independently, turn them on or off, or change the center frequency of the band-pass sigma-delta modulator 1450 and the center frequency and characteristics of the band-pass filter device 1460.
While not illustrated, it is to be appreciated that the output of each of the amplifiers respectively coupled to each of the electro-acoustic sensors 1410b, 1410c, 1410c and other electro-acoustic sensors in the group 1405 can be processed by components similar to those illustrated and discussed herein in connection with the output of the amplifier 1420.
As illustrated, a detector device 1520 can receive at least a portion of the ultrasonic signals 1540a-1540c via a microelectromechanical microphone in accordance with this disclosure. The microelectromechanical microphone can be arranged in a single-microphone configuration or in a stereophonic configuration (see, e.g.,
The processor 1550 can receive the interrupt signal and can apply logic configured to supply an alarm or trigger other type of responses, such as implementing motion sensing, noise cancellation, or beamforming; and/or executing certain module(s) within a wearable device that includes the processor 1550. In certain implementations, the alarm can be an audible or ultrasonic alarm, a haptic alarm, and/or a visual alarm.
In the detection system 1600 shown in
The example sensor hub 1720 illustrated in
As illustrated, the sensor hub 1720 can be configured to execute or otherwise implement logic configured to supply one or more alarms 1760 or to trigger other type of responses, such as implementing motion sensing, noise cancellation, or beamforming; and/or executing certain module(s) within a wearable device or another type of device integrated or functionally coupled to the sensor hub 1720. In certain implementations, at least one of the alarm(s) 1760 can be an audible or ultrasonic alarm, a haptic alarm, and/or a visual alarm.
In certain implementations, the sensor hub 1720 can be integrated into or can be functionally coupled to an infotainment system or another type of vehicular electronics in a vehicle. As such, in one example, the sensor hub 1720 can leverage the detector device 1620 to determine the presence of another vehicle by detecting ultrasonic signals in accordance with this disclosure. In other implementations, the sensor hub 1720 can be included in a mobile device.
As employed herein, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. Moreover, articles “a” and “an” as used in this specification and annexed drawings should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form.
In addition, the term “processor” can refer to substantially any computing processing unit or device including, but not limited to, single-core processors; single-processors with software multithread execution capability; multi-core processors; multi-core processors with software multithread execution capability; multi-core processors with hardware multithread technology; parallel platforms; and parallel platforms with distributed shared memory. Additionally, a processor can refer to an integrated circuit, an ASIC, a DSP, a FPGA, a programmable logic controller (PLC), a complex programmable logic device (CPLD), a discrete gate or transistor logic, discrete hardware components or any combination thereof designed to perform the functions described herein. Processors can exploit nano-scale architectures such as, but not limited to, molecular and quantum-dot based transistors, switches and gates, in order to optimize space usage or enhance performance of mobile device equipment. A processor can also be implemented as a combination of computing processing units.
Memory disclosed herein can include volatile memory or nonvolatile memory or can include both volatile and nonvolatile memory. By way of illustration, and not limitation, nonvolatile memory can include ROM, programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable PROM (EEPROM) or flash memory. Volatile memory can include RAM, which acts as external cache memory. By way of illustration and not limitation, RAM is available in many forms such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM). The memory (e.g., data storages, databases) of the embodiments is intended to include, without being limited to, these and any other suitable types of memory.
As used herein, terms such as “data storage,” “database,” and substantially any other information storage component relevant to operation and functionality of a component, refer to “memory components,” or entities embodied in a “memory” or components including the memory. It will be appreciated that the memory components or computer-readable storage media, described herein can be either volatile memory or nonvolatile memory or can include both volatile and nonvolatile memory.
In addition, the terms “example” and “such as” are utilized herein to mean serving as an instance or illustration. Any embodiment or design described herein as an “example” or referred to in connection with a “such as” clause is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the terms “example” or “such as” is intended to present concepts in a concrete fashion. The terms “first,” “second,” “third,” and so forth, as used in the claims and description, unless otherwise clear by context, is for clarity only and does not necessarily indicate or imply any order in time.
What has been described above includes examples of one or more embodiments of the disclosure. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing these examples, and it can be recognized that many further combinations and permutations of the present embodiments are possible. Accordingly, the embodiments disclosed and/or claimed herein are intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the detailed description and the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.
The present application claims priority to U.S. Provisional Patent Application No. 62/098,412, filed Dec. 31, 2014, the content of which application is hereby incorporated herein by reference in its entirety.
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