Efficient concurrent sampling at different rates

An apparatus and method for efficient and concurrent sampling of a sensor signal to create multiple output signals each at different sampling rates is provided. The apparatus and method determine an aperiodic sampling rate or sampling schedule such that only samples representing samples at the different sampling rates are taken. The aperiodic samples are taken then de-interleaved to filter wanted samples for a particular application or user. As a result, the aperiodic samples is just a combination of all of the subsets to each application. Such aperiodic sampling reduces a total number of samples taken and, as a direct result, reduces the number of samples needing to be processed and stored and also reduced the power otherwise consumed to sample, process and store unused samples.

RELATED APPLICATIONS

Not applicable.

FIELD

This disclosure relates generally to apparatus and methods for aperiodically sampling sensor data in a wireless device. More particularly, the disclosure relates to providing periodic samples to applications requiring different sampling rates from an aperiodic sampled source.

BACKGROUND

A single mobile device may allow multiple applications to execute simultaneously. Several applications requiring sensor data often run concurrently within a user's mobile device. Two or more of these applications may need sensor measurements from a common type of sensor or the same sensor. Often the requirements for sensor data from separate applications vary. That is, one application may require samples from a sensor at a first periodic sampling rate while a second application requires data from the same sensor but at a second periodic sampling rate.

Typically, applications require sensor measurements at a periodic rate but a first application may need sensor measurements often while a second application may use measurements from the same sensor less frequently. For example, a first application may require measurement every 20 milliseconds (ms) (equivalent to a sampling rate of 50 Hz) and a second application may require measurements every 25 ms (equivalent to a sampling rate of 40 Hz).

Several approaches are available to accommodate different sampling rates. In a first approach, a mobile device may provide a corresponding number of sensors, each with its own sampler. That is, if there are N applications requiring sensor measurements, there are a corresponding N or more sensors. This approach requires a number of duplicative sensors and samplers, each consuming power and requiring circuit board real estate.

A second approach includes a single sensor but a plural number of samplers. This single-sensor approach has the advantage of saving some power but disadvantages associated with having of multiple samplers.

A third approach includes a single sensor with a single sampler. With this approach, a higher over-sampled sampling rate is used such that each of the various required sampling rates are found within the over-sampled sampling rate. That is, a periodic sampling rate is selected based on the least common multiple (LCM) of the different sampling rates, which typically results in a high LCM sampling rate and a large number of unused samples. The over-sampled sampling rate is the smallest number that is a multiple of each of the required sampling rates. For example, the LCM of 50 Hz (sampling rate of first application) and 40 Hz (sampling rate of first application) is 200 Hz (sampling rate of sampler). In this case, the sampler provides samples at a rate four times what is necessary for the first application and five times what is necessary for the second application.

Of the several approaches available, each having its various drawbacks in extra hardware requirements, power consumption and time necessary to process unused samples.

SUMMARY OF THE DISCLOSURE

An apparatus and method for efficient and concurrent sampling of a sensor signal to create multiple output signals each at different sampling rates are provided.

Embodiments determine an aperiodic sampling rate or sampling schedule such that only samples representing samples at the different sampling rates are taken. The aperiodic samples are taken then de-interleaved to filter out wanted samples for a particular application or user. For example, a first subset of the aperiodic samples are routed to a first application at a first periodic sampling rate, and a second overlapping subset of the aperiodic samples are routed to a second application at a different second periodic sampling rate. As a result, the aperiodic samples are just a combination of all of the subsets. Typically, such aperiodic sampling reduces a total number of samples taken and, as a direct result, reduces the number of samples needing to be processed and stored and also reduced the power otherwise consumed to sample, process and store unused samples.

According to some aspects, disclosed is a method of providing a sensor signal to multiple applications in a mobile device, each requiring a different sampling rate, the method comprising: sampling the sensor signal at an aperiodic sampling rate resulting in aperiodic samples; and de-interleaving the aperiodic samples comprising routing to a first application a first subset of the aperiodic samples, wherein the first subset represents samples at a first periodic sampling rate; and routing to a second application a second subset of the aperiodic samples, wherein the second subset represents samples at a second periodic sampling rate, and wherein the first periodic sample rate differs from the second periodic sampling rate.

According to some aspects, disclosed is a mobile device for providing a sensor signal to multiple applications in a mobile device, each requiring a different sampling rate, the device comprising: a sampler comprising an input port to couple to the sensor signal, a control port to couple to an aperiodic trigger based on an aperiodic sampling rate, and an output port to provide aperiodic samples at the aperiodic sampling rate; and a de-interleaver comprising an input port to couple to the aperiodic samples, a first output port to route to a first application a first subset of the aperiodic samples at a first periodic sampling rate, and a second output port to route to a second application a second subset of the aperiodic samples at a second periodic sampling rate; wherein the first and second periodic sample rates are different.

According to some aspects, disclosed is a mobile device for providing a sensor signal to multiple applications in the mobile device, each requiring a different sampling rate, the device comprising: means for sampling the sensor signal at an aperiodic sampling rate resulting in aperiodic samples; and means for de-interleaving the aperiodic samples comprising means for routing a first application a first subset of the aperiodic samples, wherein the first subset represents samples at a first periodic sampling rate; and means for routing a second application a second subset of the aperiodic samples, wherein the second subset represents samples at a second periodic sampling rate, wherein the first periodic sample rate differs from the second periodic sampling rate.

According to some aspects, disclosed is a mobile device for providing a sensor signal to multiple applications in the mobile device, each requiring a different sampling rate, the device comprising a processor and a memory wherein the memory includes software instructions to: instruct a sampler to sample the sensor signal at an aperiodic sampling rate resulting in aperiodic samples; and de-interleave the aperiodic samples comprising software instructions to route a first application a first subset of the aperiodic samples, wherein the first subset represents samples at a first periodic sampling rate; and route a second application a second subset of the aperiodic samples, wherein the second subset represents samples at a second periodic sampling rate, wherein the first periodic sample rate differs from the second periodic sampling rate.

According to some aspects, disclosed is a computer-readable medium including program code stored thereon, comprising program code to: instruct a sampler to sample the sensor signal at an aperiodic sampling rate resulting in aperiodic samples; and de-interleave the aperiodic samples comprising program code to route a first application a first subset of the aperiodic samples, wherein the first subset represents samples at a first periodic sampling rate; and route a second application a second subset of the aperiodic samples, wherein the second subset represents samples at a second periodic sampling rate, wherein the first periodic sample rate differs from the second periodic sampling rate.

It is understood that other aspects will become readily apparent to those skilled in the art from the following detailed description, wherein it is shown and described various aspects by way of illustration. The drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various aspects of the present disclosure and is not intended to represent the only aspects in which the present disclosure may be practiced. Each aspect described in this disclosure is provided merely as an example or illustration of the present disclosure, and should not necessarily be construed as preferred or advantageous over other aspects. The detailed description includes specific details for the purpose of providing a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the present disclosure. Acronyms and other descriptive terminology may be used merely for convenience and clarity and are not intended to limit the scope of the disclosure.

With each of the approaches describe above, one or more samplers each having a periodic sampling rate. In accordance to embodiments of the present invention, however, a single sampler is used and has an aperiodic sampling rate is used.

FIG. 1shows two applications receiving samples from a common sensor via separate samplers. According to the second approach described above, one sensor10is connected to two samplers40. The sensor10provides a common sensor signal20to both samplers40, which in turn provides corresponding samples71,72to applications1001,1002. A first sampler40receives a first trigger61. The first trigger61carries a first periodic sampling rate51(e.g., 50 Hz). The first sampler40provides resulting samples71at the first periodic sampling rate51to a first application1001. Similarly, a second sampler40receives a second trigger62. The second trigger62carries a second periodic sampling rate52(e.g., 40 Hz). The second sampler40provides resulting samples72at the second periodic sampling52rate to a second application1002. Again, this approach has the disadvantage of multiple samplers, on for each application requiring sensor samples from a common sensor. Also, sampling requests from multiple samplers may collide at the sensor, thus the sensor may not be able to receive each sampling command.

FIG. 2shows a mobile device, which oversamples a sensor signal at a high periodic rate in order to effectively provide samples at two lower sampling rates. Instead of two separate samples, a single sampler40accepts a sensor signal20from a sensor10. The sampler is triggered by a triggering signal (LCM-sampling trigger160), which operates at a periodic sampling rate (periodic LCM-sampling rate150) and provides LCM samples180at a periodic over-sampled sample rate (LCM-sampling rate180). This LCM-sampled rate150is set to the least common multiple (LCM) of two or more different periodic sampling rates required by a corresponding two or more different applications.

The LCM-sampling rate150is higher than the data rates required by the applications. In a typical architecture, the LCM samples180pass from the sampler40to a periodic de-interleaver110via a bus80. At the higher LCM-sampling rate150, bus transitions require significantly more power than would be required at one of the sample rates required by one of the applications. The periodic de-interleaver110acts as a multiplexer or switch to provide the various application only the samples that each needs and discards the remaining samples. In the case shown, the periodic de-interleaver110accepts the LCM samples180arriving at the periodic LCM-sampling rate, diverts samples71at a first sampling rate required by a first application1001, diverts samples72at a second sampling rate required by a second application1002, and discards the remaining unwanted samples. Therefore, depending on timing, each particular sample from the LCM samples180will be: (1) forwarded to just a single application; (2) forwarded to two or more applications; or (3) discarded and not provided to any application. A controller120generates the LCM-sampling trigger160based on the periodic LCM-sampling rate150, which is in turn based on the first and second periodic sampling rates51,52. The control120may also provide a de-interleaving control signal170to be used by the periodic de-interleaver110to route or parse the incoming LCM samples180. The periodic de-interleaver110and controller120, as well as the first and second applications1001,1002, may each execute as routines on a processor100. Alternatively, the periodic de-interleaver110and controller120may be implemented in hardware or as a combination of hardware and software.

FIGS. 3A and 3Bshow an example of a first periodic schedule for sampling a sensor signal at a first periodic sampling rate and a second periodic schedule for sampling a sensor signal at a second periodic sampling rate.FIG. 3Ashows timing for samples71used in a first application1001requiring at a first periodic sampling rate51(e.g., every 20 ms at times {t, t+20, t+40, t+60, t+80, t+100, . . . } or at a rate of 50 Hz) beginning at a time t.FIG. 3Bshows timing for samples72used in a second application1002requiring at a second periodic sampling rate52(e.g., every 25 ms at times {t, t+25, t+50, t+75, t+100, . . . } or at a rate of 40 Hz) beginning at the time t. In this example, samples71and72for the first and second applications have common samples at time {t, t+100, t+200, . . . }.

FIGS. 4A and 4Bshow an example of a periodic sampling schedule for over sampling a sensor signal at a periodic over-sampling rate and a corresponding over-sampling triggering signal. InFIG. 4A, samples180are taken at a rate much higher than either the first or second periodic sampling rates51,52. The periodic LCM-sampling rate150is selected to be equal to the LCM of the first and second periodic sampling rates51and52. In the example provided, a sampler40operating at the periodic LCM-sampling rate150is produces samples180every 5 ms at times {t, t+5, t+10, t+15, t+20, . . . } or at a rate of 200 Hz.FIG. 4Bshows a corresponding LCM-sampling trigger signal160with a negative edge every 5 ms resulting in a periodic triggering signal of 200 Hz.

The high rate of the periodic triggering signal160results in frequent data bit transition on bus30and a majority of the samples taken may never be used by any applications. For example, in the example described above: (1) 4 of every 20 samples are used just by the first application1001; (2) 3 of every 20 samples are used just by the second application1002; and (3) 1 of every 20 samples is used by the first and second applications1001,1002. As a result, the remaining 12 of 20 samples are discarded. These unnecessary samples consumed power to produce at the sampler40and consumed power at the bus80for data transitions.

Embodiments of the present invention reduce the power otherwise consumed by reducing a number of total samples taken and, as a result, reducing a number of total bus transitions.

FIGS. 5A and 5Bshow an example of an aperiodic sampling schedule for sampling a sensor signal at an aperiodic sampling rate and a corresponding aperiodic triggering signal, in accordance with some embodiments of the present invention.

InFIG. 5A, samples are shown at times needed by at least one of the applications. The first and second applications1001,1002require samples at a first sampling rate51and second sampling rate52. The sampler40produces samples280just when at least one of the two applications requires a sample. As a result, the samples280occur at an aperiodic sampling rate250. Unnecessary samples are not taken by sampler40. For example, if the first and second periodic sampling rates51and52are 50 Hz and 40 Hz, respectfully, the samples will occur at times {t, t+20, t+25, t+40, t+50, t+60, t+75, t+80, t+100, . . . }. An aperiodic sampling rate250is derived from multiple periodic sample rates. For example, a first periodic sampling rate may be N times a base rate and a second periodic sampling rate may be M times the base rate, where N and M are different positive integers. In addition, in some cases, the ratios of N to M and M to N are both non-integers. Also, in some cases, the N and M are both greater than one. Based on the periodic sampling rates, the resulting periodic subsets of samples may overlap (i.e., have some common samples).

FIG. 5Bshows a corresponding aperiodic trigger signal260, which occurs at a time corresponding to when each sample is needed. The aperiodic trigger signal260is used by the sampler40to trigger each raw sample.

In some embodiments, a timer is used to generate the aperiodic triggering signal260. For the example shown and considering time t as the current time, a timer may be set to expire after a first duration (D1=|(t+20)−t|). Based on the timer expiring after the first duration of time at time t+20, a transition is provided on the aperiodic triggering signal260and the timer is reset to expire after a second duration (D2=|(t+25)−(t+20)|). The timer next expires after the second duration of time at time t+25. Based on the timer expiring after the second duration, another transition is provided on the aperiodic triggering signal260and the timer is reset to expire after a third duration (D3=|(t+40)−(t+25)|). For an aperiodic sampling rate, the first, second and third durations are not necessarily equal. In this example, the first duration is 20 ms, the second duration is 5 ms and the third duration is 15 ms. For periodic samples, the duration between successive samples is a constant time.

FIG. 6illustrates a mobile device for providing a sensor signal to multiple applications, each requiring a different sampling rate, in accordance with some embodiments of the present invention. It is understood that some embodiments will have at least two applications that require the same sampling rate, while another application requires a different sampling rate. The mobile device1includes a sensor10, a sampler40, a processor200and a bus80coupling the sampler to the processor200. The processor200includes memory230, a controller220, an aperiodic de-interleaver210and first and second applications1001,1002. The controller220, an aperiodic de-interleaver210and applications may each be modules running on the processor200. Each module may be software to perform the functions of the module. The sensor10provides an analog sensor signal20to the sampler40. The sampler40includes an input port to couple to the sensor signal20, a control port to couple to an aperiodic triggering signal260, which is based on an aperiodic sampling rate250, and an output port to provide aperiodic samples280at the aperiodic sampling rate250. Based on timing provided by an aperiodic triggering signal260, which provides negative transitions at an aperiodic sampling rate250, the sampler40provides samples280to the processor200via a bus80. The sampler40acts as a means for sampling the sensor signal20at an aperiodic sampling rate250resulting in aperiodic samples280.

As noted above, excessive bus transitions consume significantly more power with high rate periodic sampling. Using the lower rate aperiodic sampling, consumption of power on the bus is greatly reduced. The samples280are digitized versions of the analog sensor signal20at the transitions supplied by the aperiodic triggering signal260. The aperiodic de-interleaver210copies the incoming samples280for use by the separate applications1001,1002. The aperiodic de-interleaver210acts as a means for de-interleaving. The aperiodic de-interleaver210includes an input port to couple to the aperiodic samples280, a first output port to route to a first application1001a first subset of the aperiodic samples71at a first periodic sampling rate51, and a second output port to route to a second application1002a second subset of the aperiodic samples72at a second periodic sampling rate52. A combination of all of the subsets of periodic samples results in the aperiodic samples280. As noted above, the first and second periodic sample rates are different. The aperiodic de-interleaver210may also include a first control port to couple to the first periodic sampling rate and a second control port to couple to the second periodic sampling rate. The first and second periodic sampling rates may be represented by the de-interleaving control signal270.

The aperiodic de-interleaver210may use memory230to store or buffer samples280in one buffer or a buffer corresponding to each application. In this manner, each sample280entering the aperiodic de-interleaver210is supplied to one or more of the applications. For example, a first sample280is provided to both the first and second applications1001,1002as sample71to the first application1001and as sample72to the second application1002. A second sample280is provided to just the first application1001as sample71. A third sample280is provided to just the second application1002as sample72. Thus, the first application1001receives samples71at the first periodic sampling rate51and the second application1002receives samples72at the second periodic sampling rate52. Therefore, depending on timing, each particular sample from the aperiodic samples280will be either: (1) forwarded to just a single application; or (2) forwarded to two or more applications. No samples280are discarded. As such, each sample280is provided to at least one application.

Control for determining which one or more applications receive a particular sample280is determined by a de-interleaving control signal270generated by the controller220. The de-interleaving control signal270may be a separate control signal for each application, which indicates whether a particular sample280will be passed to a particular application represented by that control signal. Alternatively, the de-interleaving control signal270may be a schedule, which the aperiodic de-interleaver210interprets to determine routing of incoming samples280.

The controller220sets the de-interleaving control signal270and the aperiodic triggering signal260based on the required periodic sampling rates. For example, a first and second periodic sampling rates51,52are provided to the controller220. The controller220determines a sampling schedule based on these required periodic rates. Depending on the applications' requirements, a multiple of one rate may equal the other rate. In these cases, a periodic sampling rate equal to the larger of the two rates is used. In some cases, applications may require two different periodic sampling rates such that a multiple N of first required periodic sampling rate equals a multiple M of a second required periodic sampling rate (i.e., N*R1=M*R2, where R1is a first periodic sampling rate and R2 is a first periodic sampling rate), where N and M are unequal, positive integers greater than one. In these cases, the de-interleaver210will periodically supply a common sample280to both applications during the course of de-interleaving the samples. In some cases, a first periodic sampling rate is N times a base rate and the second periodic sampling rate is M times the base rate, wherein N and M are positive integers and wherein ratios of N to M and M to N are both non-integers. In cases where N and M are unequal, positive integers greater than one, samples71and samples72are overlapping subsets. In each case, samples71and samples72combine to form a set of samples represented by samples280.

FIG. 7diagrams a flowchart of a mobile device for providing a sensor signal to multiple applications, each requiring a different sampling rate, in accordance with some embodiments of the present invention.

At310, the mobile device1receives a request for samples71at a first periodic sampling rate51from a first application1001. At320, the mobile device1receives a request for samples72at a second periodic sampling rate52from a second application1002, wherein the first and second periodic sampling rates are different. The first and second application1001,1002may reside within mobile device1as code executing on the processor200.

At330, the mobile device1determines an aperiodic sampling rate250based on the first and the second periodic sampling rates51,52. This flowchart may be expanded with a third application requiring a third periodic sampling rate. The mobile device1could receive a request for samples at a third periodic sampling rate from a third application. Then at330, the mobile device1determines an aperiodic sampling rate250based on the three periodic sampling rates.

At340, the mobile device1samples a sensor signal20at the aperiodic sampling rate250resulting in aperiodic samples280. At350, the mobile device1writes the aperiodic samples to memory230. The memory230may be a single input register on the processor200, a pair of memory locations, one memory location for each application, a buffer for incoming samples, or a buffer for each application.

At360and370, the mobile device1de-interleaves the aperiodic samples for the first and second applications1001,1002, thereby routing the first application1001a first subset of the aperiodic samples71and routing the second application1002a second subset of the aperiodic samples72. The first subset71represents samples at the first periodic sampling rate51. Similarly, the second subset72represents samples at the second periodic sampling rate52. In the case of one or more additional applications, the act of de-interleaving the aperiodic samples280further comprises routing to the third application a third subset of the aperiodic samples, wherein the third subset represents samples at the third periodic sampling rate.

FIG. 8shows a messaging diagram of a mobile device for providing a sensor signal to multiple applications, each requiring a different sampling rate, in accordance with some embodiments of the present invention. The mobile device includes a sensor10, a sampler40, and processor200with a controller220and de-interleaver210running a first, second and third applications1001,1002,1003. The sensor10provides an analog sensor signal20to a sampler40.

At310, the first application1001sends a request for samples71at a first periodic sampling rate51. At320, the second application1002sends a request for samples72at a second periodic sampling rate52. At322, the third application1003sends a request for samples73at a third periodic sampling rate53. The request are received by a controller module220in the processor200and may arrive in or out of order and at scheduled times. The requests may be initiated by the applications and pushed to the controller220, or may be pulled from the applications by the controller220.

At330and based on requested sampling rates received so far (e.g., the second and third rates have been requested but the first rate request has not been received yet), the controller220determines an aperiodic sampling rate250and generates an aperiodic triggering signal260based on the determined aperiodic sampling rate250to the sampler40. The aperiodic triggering signal260may be a pulsed signal (as shown inFIG. 5B) or may be in the form of digital control commands. The controller220updates this aperiodic triggering signal260as additional requests for a new sampling rate are received and as requests for old sampling rates expire.

The sampler40receives the aperiodic triggering signal260and the analog sensor signal20continuously generated by the sensor10while the sensor10is in an activated mode. At270and in response to the aperiodic triggering signal260, the sampler40returns samples280at the aperiodic sampling rate250. This process continues until the aperiodic triggering signal260updates to a new aperiodic sampling rate or terminates sampling.

At360and370, the aperiodic de-interleaver210de-interleaves the received aperiodic samples280. The aperiodic de-interleaver210receives stream of aperiodic samples280and routes or parses out periodic streams of samples (e.g., periodic samples71at the first sampling rate51for the first application1001, periodic samples72at the second sampling rate52for the second application1002, and periodic samples73at the third sampling rate53for the third application1003).

FIG. 9illustrates a processor in a mobile device for providing a sensor signal to multiple applications, each requiring a different sampling rate, in accordance with some embodiments of the present invention. The mobile device includes a processor200with an aperiodic de-interleaver210, a controller220and a first, second, third and fourth applications1001,1002,1003,1004. The controller220receives a respective four periodic sampling rates51,52,53,54, determines an aperiodic sampling rate250based on the four periodic sampling rates51,52,53,54, generates an aperiodic triggering signal260for the sampler40based on the aperiodic sampling rate250, and generates a de-interleaving control signal270also based on the aperiodic sampling rate250. The aperiodic de-interleaver210routes or parses the incoming samples280each to the appropriate one or more applications1001,1002,1003,1004, based on the de-interleaving control signal270to create the respective periodic sample streams71,72,73,74.

FIG. 10shows an aperiodic de-interleaver, in accordance with some embodiments of the present invention. The aperiodic de-interleaver210includes one switch for each output stream71,72,73,74. The switches act as a means for routing or parsing subsets of the aperiodic samples to the respective applications. Each switch is controlled by a separate control derived from the de-interleaving control signal270. For example, a first switch couples the aperiodic samples280to the periodic sample stream71. The switch may be implemented in hardware or software. If in software, the aperiodic de-interleaver210copies an incoming sample from the aperiodic samples280to a memory location such that the first application may receive the sample as the next sample in the periodic samples71.

FIG. 11illustrates a timing diagram showing a minimum duration between samples, in accordance with some embodiments of the present invention. Often a sampler requires a minimum duration ‘D’ between samples, which is usually represented by a maximum sampling frequency 1/D in Hertz. In these cases, the controller220or sampler40may delay the triggering time to comply with the minimum spacing. For example, if the last sample was taken at time t, and the next sample is scheduled to be taken as tkbut |ti−tk|<D, the controller220may shift the next time to occur at time ti+1, where |ti−ti+1=D. Alternatively, the controller220or sampler40may advance the triggering time to avoid the minimum spacing issue. For example, if the last sample was taken at time t, and the next sample is scheduled to be taken as tkbut |ti−tk|<D, the controller220or sampler40may skip sampling at time tk(or time ti+1) and use the sample at time t, to represent a sample at time tk. Alternatively, the controller220or sampler40may advance or delay the triggering time. For example, if the last sample was taken at time t, and the next sample is scheduled to be taken as tkand if |ti−tk|<D/2, the controller220may skip sampling at time tk(or time ti+1) and use the sample at time tito represent a sample at time tk. If D/2<|ti−tk|<D, the controller220or sampler40may shift the next time to occur at time ti+1, where |ti−ti+1|=D.

As indicated, the above-described modules may be implemented individually or in combination as software instructions. These software instructions may be saved as program code on a computer-readable medium for later execution on a processor200. Furthermore, a mobile device1may include a processor200and memory230, wherein the memory230includes these software instructions to execute one or more of these modules.

The previous description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the spirit or scope of the disclosure.