Patent Description:
Wireless communication signals are transmitted from a transmitting device to a receiving device. In many cases, the transmitting device transmits a carrier signal. One broad category of modulation schemes is amplitude-shift keying (ASK). In an ASK modulation scheme, information is transmitted by modulating the amplitude of the carrier signal. A low amplitude may signify a binary value of <NUM>. A high amplitude may signify a binary value of <NUM>.

Among the category of ASK modulation schemes, there are various subcategories. In some schemes, information is transmitted not by the amplitude level but by transitions in the amplitude of the carrier signal (Manchester encoding). The advantage is that transitions support the recovery of the clock, and for this reason these schemes are also called self-clocking. For example, a binary <NUM> may be encoded as binary <NUM>, which corresponds to a low to high transition. A binary <NUM> may be encoded as binary <NUM>, which corresponds to a high to low transition. Transitions happen in the middle of the bit interval to support clock recovery. There can also be transitions at the bit boundary to set the carrier amplitude at the right level. In another case, information is encoded based on the presence or absence of a transition in the middle of the bit interval (Differential Manchester Encoding). For example, a binary <NUM> may be encoded as binary <NUM> or <NUM> (no transition in the middle of the bit interval). A binary <NUM> may be encoded as binary <NUM> or <NUM> (transition is present in the middle of the bit interval). The encoding pattern is chosen to guarantee a transition at the bit boundary to support clock recovery.

One issue that arises in some ASK modulation schemes, is that the modulated carrier may have a larger bandwidth depending on the type of data. For example, in some ASK modulation schemes a stream of binary <NUM> may be encoded as <NUM>. , a stream of binary <NUM> may be encoded as <NUM>. , and alternating <NUM> and <NUM> may be encoded as <NUM>. The latter stream has half the bandwidth with respect to the former two streams.

In some ASK modulation schemes, a stream of binary <NUM> is encoded as <NUM>. and a stream of binary <NUM> is encoded as <NUM>. Again, the latter stream has half the bandwidth with respect to the former. The effect of this is that at the receiving end, filters with larger bandwidth are utilized and a higher sampling frequency can be called for to decode streams of one type of binary value (e.g. all <NUM> or all <NUM>) versus streams of the other type of binary value. This can reduce the performance and increase the cost and complexity of the receiving device.

Document <CIT> (<NUM>-<NUM>-<NUM>) provides an ASK demodulation device, which demodulates a modulated signal, which is ASK-modulated with a Manchester-encoded data sequence. The ASK demodulation device may comprise a low-pass filter connected to a previous or following stage of a data extraction section to remove a high frequency component included in an input signal. Preferably, the low-pass filter may be an integration filter for integrating the input signal for a predetermined time period.

Embodiments of the present disclosure provide a receiving electronic device of a wireless communication system that decodes data utilizing a receiving bandwidth corresponding to the lower of two frequencies present in a modulated carrier signal received by the receiving device. In particular, the receiving device utilizes a low-pass filter that filters out signal features corresponding to the larger bandwidth. The electronic device accomplishes this without losing the data corresponding to the larger bandwidth.

The receiving electronic device can receive a self-clocked ASK modulated signal and convert the self-clocked ASK modulated signal to an on-off keyed (OOK) signal by passing the ASK signal through the low-pass filter. The higher frequencies are totally rejected by the low-pass filter, resulting in a zero amplitude for bits having the larger modulated bandwidth and a nonzero amplitude for bits having the smaller modulated bandwidth. The bits having the larger modulated bandwidth can be recovered based on the duration of time between nonzero amplitude events.

This provides several benefits. A lower frequency clock can be used in the receiving device without losing the bits associated with the larger bandwidth in the received signal. Out of band noise is more effectively rejected due to the narrower passband of the filters on the receiver side. For the same reason, very near interferents can also be rejected. Thus, a receiving device in accordance with principles of the present disclosure is more power efficient and more tolerant to noise.

The bitrate and the corresponding bandwidth can be too large for a communication channel, or the bandwidth offered by the communication channel can be too narrow to allow the bits having the larger modulated bandwidth pass without distortion. A receiving device in accordance with principles of the present disclosure would still be able to receive and decode the data stream without errors.

<FIG> is a block diagram of a wireless communication system <NUM>, according to one embodiment. The wireless communication system <NUM> includes a receiving electronic device <NUM> and a transmitting electronic device <NUM>. The transmitting electronic device <NUM> and the receiving electronic device <NUM> communicate with each other utilizing wireless communication technology.

The receiving electronic device <NUM> includes receiving circuitry <NUM>. The receiving circuitry <NUM> receives wireless signals from the transmitting electronic device. The receiving circuitry <NUM> may include one or more antenna coils, one or more receiving clocks, one or more controllers, and one or more memories. The receiving circuitry <NUM> enables the receiving electronic device <NUM> to receive the wireless signal from the transmitting electronic device <NUM> and to read data encoded into the wireless signal.

The receiving circuitry <NUM> of the receiving electronic device <NUM> includes a filter <NUM>. As will be set forth in more detail below, the filter <NUM> enables the receiving circuitry <NUM> to receive a wireless signal from the transmitting electronic device <NUM> including both large bandwidth data values and small bandwidth data values and to filter out features of the large bandwidth data values without losing the data associated with the large bandwidth data values.

<FIG> includes a graph <NUM> illustrating a carrier signal. With reference to both <FIG> and <FIG>, the graph <NUM> corresponds to the carrier signal output from the transmitting electronic device <NUM>. The carrier signal is a radiofrequency signal that facilitates wireless communication. The carrier signal may include a substantially sinusoidal waveform, a square waveform, or other types of waveforms.

Data may be encoded into the carrier signal by the transmitting electronic device <NUM>. The data may be encoded into the carrier signal by modulating the carrier signal. Various modulation schemes may be utilized to encode data into the carrier signal.

One type of modulation scheme is an ASK modulation scheme. The graph <NUM> in <FIG> illustrates a basic ASK modulation scheme. In the ASK modulation scheme, data is encoded into the carrier signal by modulating the amplitude of the carrier signal. The graph <NUM> of <FIG> illustrates a series of data values. The graph <NUM> illustrates the amplitude of the carrier signal during each of these data values. A binary <NUM> is encoded into the carrier signal by reducing the amplitude of the carrier signal. A binary <NUM> is encoded to the carrier signal by either increasing the amplitude of the carrier signal or by maintaining the carrier signal at the standard amplitude. As can be seen from the graph <NUM> and <NUM>, when the encoded value is binary zero, the carrier signal in the graph <NUM> has a low amplitude. When the encoded value is a binary <NUM>, the carrier signal of the graph <NUM> has a high amplitude, or an amplitude substantially equal to the unmodulated carrier signal. Alternatively, binary <NUM> can be encoded with low amplitudes and binary <NUM> can be encoded with high amplitudes. As will be set forth in more detail below, there are various types of modulation schemes that fit in the category of ASK modulation schemes.

Another type of modulation scheme is an OOK modulation scheme. The graph <NUM> in <FIG> illustrates the basic concepts of an OOK modulation scheme. In the OOK modulation scheme, data is encoded into the carrier signal by turning the carrier signal on and off. A data value of <NUM> may be encoded into the carrier signal by entirely turning off the carrier signal or reducing the amplitude of the carrier signal to substantially zero. A data value of <NUM> may be encoded into the carrier signal by turning on the carrier signal. Accordingly, the amplitude of the carrier signal is reduced to zero when encoding a <NUM> into the carrier signal. The amplitude of the carrier signal is maintained at the standard level when a <NUM> is encoded into the carrier signal. Alternatively, a <NUM> may be encoded by turning off the carrier signal and the <NUM> may be encoded by turning on the carrier signal.

In some cases, the level of the carrier signal is not enough to enable the receiving electronic device <NUM> to decode the data encoded into the carrier signal. Knowing the sampling clock, i.e., the bit boundaries and interval by which data is encoded into the carrier signal, enables the receiving electronic device <NUM> to sample and decode the data from the carrier signal. The clock signal could be sent separately from the carrier signal in order to keep synchronization and avoid bit slips. The clock signal can also be sent together with the data by using certain types of encoding.

One example of a self-clocking ASK scheme is Manchester encoding. In Manchester encoding, information is transmitted by transitions in the amplitude of the signal carrier. In particular, the direction of the transition determines the bit. For example, <NUM> is encoded as <NUM> which corresponds to a low-to-high transition, <NUM> is encoded as "<NUM>" which corresponds to a high-to-low transition. There is always a transition in the middle of the bit interval. The clock signal can be extracted from the transitions. Transitions may also happen at the bit boundary to set the carrier at the right level.

Another example of a self-clocking ASK encoding scheme is differential Manchester encoding. In differential Manchester encoding, information is again transmitted by transitions in the amplitude of the carrier signal, but in this case, the presence or absence of a transition in the middle of the bit interval determines the bit. For example, <NUM> is encoded as <NUM> or <NUM> without a transition in the middle. <NUM> is encoded as <NUM> or <NUM> with a transition in the middle. The encoding pattern is chosen to guarantee the transition at the bit boundary. For this reason the clock signal can be extracted from the presence of a transition at the bit boundary.

<FIG> includes a plurality of graphs illustrating various data patterns with differential Manchester encoding, according to one embodiment. Graph <NUM> illustrates a series of all <NUM> encoded into the carrier signal with differential Manchester encoding. Graph <NUM> illustrates a series of all <NUM> encoded into the carrier signal with differential Manchester encoding. Graph <NUM> includes a mix of <NUM> and <NUM>.

As can be seen from graphs <NUM> and <NUM>, a sequence of all <NUM> utilizes twice the bandwidth as a sequence of all <NUM> in differential Manchester encoding. The pulse width of a <NUM> is half the pulse width of a <NUM>. Accordingly, the frequency associated with binary <NUM> in differential Manchester encoding is effectively double the frequency associated with binary <NUM> in differential Manchester encoding.

With reference to <FIG> and <FIG>, if the transmitting electronic device <NUM> transmits data by encoding the carrier signal with a differential Manchester encoding scheme, then the receiving electronic device <NUM> could be expected to utilize a receiving clock or sampling rate associated with the higher frequency of the binary <NUM>. However, in some cases it may not be possible, or may be too power intensive, for a receiving electronic device to utilize the higher frequency or sampling. Also in some case the transmission channel may not offer the large bandwidth that would typically be utilized by the high frequency in the modulated carrier, therefore the received waveform is heavily distorted.

The receiving electronic device <NUM> overcomes these drawbacks by utilizing the filter <NUM>. In particular, the receiving electronic device <NUM> utilizes the filter <NUM> to filter out all frequencies higher than the frequency associated with the binary <NUM> in the differential Manchester encoding scheme. The low-pass filter <NUM> is, thus, a low-pass filter with a cutoff frequency between the lower frequency associated with the binary <NUM> and a higher frequency associated with the binary <NUM>.

The electronic device <NUM> effectively converts the ASK modulated wireless signal received from the transmitting electronic device <NUM> to an OOK modulated signal. In particular, because signal features associated with <NUM> are filtered out by the filter <NUM>, the signal becomes an OOK signal in which <NUM> have zero amplitude and <NUM> have nonzero amplitude. The <NUM> have nonzero amplitude because they have a frequency that is less than a cutoff frequency of the low-pass filter <NUM>.

Because the electronic device <NUM> converts the ASK modulated signal to an OOK modulated signal in which only the <NUM> have amplitude, the receiving electronic device <NUM> does not need a sampling rate associated with the higher frequency of the <NUM> in the differential Manchester ASK signal received from the transmitting electronic device <NUM>. The receiving electronic device <NUM> can extract the <NUM> from the OOK signal in substantially the same manner as extracting <NUM> in traditional OOK signals. In particular, a gap between nonzero amplitude features, or the gap between a falling edge and a rising edge of the OOK signal indicates the presence of one or more binary <NUM>. The time duration or length of the gap between nonzero amplitudes or high amplitudes indicates the number of <NUM> present.

<FIG> includes graphs of a plurality of wireless signals received by the receiving electronic device <NUM> from the transmitting electronic device <NUM> and initially demodulated, according to one embodiment. Before demodulation, the signals of <FIG> were received in a differential Manchester ASK encoding scheme. The graph <NUM> represents a stream of all <NUM>. The graph <NUM> represents a mixed stream of <NUM> and <NUM>, with more <NUM> than <NUM>. The graph <NUM> represents a mixed stream of <NUM> and <NUM> with substantially equal numbers of <NUM> and <NUM>. The graph <NUM> represents a mixed stream of <NUM> and <NUM>, with more <NUM> than <NUM>. The graph <NUM> represents a stream of all <NUM>. The graphs <NUM>-<NUM> illustrate the frequency differences associated with <NUM> and <NUM> in the differential Manchester encoding scheme. In particular, the frequency associated with <NUM> is substantially double the frequency associated with <NUM>.

<FIG> includes graphs corresponding to the signals of <FIG> after being passed through an edge detector, according to one embodiment. The graph <NUM> corresponds to the graph <NUM> after being passed through the edge detector. The graph <NUM> corresponds to the graph <NUM> after being passed through the edge detector. The graph <NUM> corresponds to the graph <NUM> after being passed through the edge detector. The graph <NUM> corresponds to the graph <NUM> after being passed through the edge detector. The graph <NUM> corresponds to the graph <NUM> after being passed through the edge detector. The edge detector may be part of the receiving circuitry <NUM> of the receiving electronic device <NUM> of <FIG>.

<FIG> includes graphs corresponding to the signals of <FIG> after being passed through the low-pass filter <NUM> of the receiving electronic device <NUM> of <FIG>, according to one embodiment. The graph <NUM> corresponds to the graph <NUM> after being passed through the low-pass filter <NUM>. The graph <NUM> corresponds to the graph <NUM> after being passed through the low-pass filter <NUM>. The graph <NUM> corresponds to the graph <NUM> after being passed through the low-pass filter <NUM>. The graph <NUM> corresponds to the graph <NUM> after being passed through the low-pass filter <NUM>. The graph <NUM> corresponds to the graph <NUM> after being passed through the low-pass filter <NUM>.

<FIG> illustrates that the higher frequency features associated with the numeral <NUM> are entirely absent after being passed to the low-pass filter <NUM>. The graph <NUM> illustrates that a stream of all <NUM> results in a signal having no amplitude. The graph <NUM> illustrates that a stream of all <NUM> results in a signal having a frequency associated with the lower frequency of the <NUM> of the differential Manchester encoding scheme. In each of the signals <NUM>-<NUM>, the higher frequency features associated with <NUM> in the differential Manchester encoding scheme are gone.

The graphs of <FIG> correspond to an OOK modulated signal. In the OOK signals of <FIG>, <NUM> are represented by durations of substantially no amplitude. In the OOK signals of <FIG>, <NUM> are represented by durations of nonzero amplitude. As described previously, <NUM> can be extracted from the OOK signal by determining the duration of substantially zero amplitude periods between nonzero amplitude periods. In practice, other signal processing or conditioning may be performed on the signals of <FIG> prior to the decoding or retrieving the data from the OOK signal. For example, signal processing or conditioning may convert the sharp features of the graphs <NUM>-<NUM> to substantially square wave like features. Various other types of signal processing or conditioning may be performed without departing from the scope of the present disclosure.

While embodiments have been described in which differential Manchester encoded signals are converted to an OOK signal in which <NUM> have no amplitude and <NUM> have nonzero amplitude, other types of encoding schemes can be utilized without departing from the scope of the present disclosure. For example, other types of ASK encoding signals can be converted to other types of OOK signals.

One benefit of the narrower bandwidth associated with the filter <NUM> is that more out-of-band noise is rejected. Another benefit is that very near interferents can be rejected. An interferent at the bit rate frequency can also be rejected. These interferents may be created by non-linearities in a transmission channel or in analog receiving and demodulation circuits (mixers and filters). Interferents created by non-linearities are very difficult to remove by means of linear processing techniques, such as adaptive equalization filters. Adaptive filters may fail to converge to the correct solution and even when they converge, the linear compensation of non-linearities may be insufficient. Application of the filter <NUM> the receiving electronic device <NUM> more tolerant to noise, and robust against near interferents and especially interferents created by non-linearities. This implementation is non-adaptive and eliminates the probabilistic behavior of adaptive filters which may fail at run time. This result in a smaller circuit area, lower power consumption, lower bit error rate.

Another benefit is that the receiver in accordance with the disclosure becomes insensitive to distortions associated to larger frequencies when the communication channel has a bandwidth smaller than what would be required to pass the larger frequencies. If everything else is kept equal, the receiver in accordance with the disclosure would support successful decoding of a higher communication bitrate (twice the rate allowed by classic ASK receivers).

In one example, the received signal is sampled and demodulated to have <NUM> samples per bit interval. Differential Manchester encoding is utilized. The low-pass filter <NUM> is configured with a cutoff frequency = Fbit (moving average over <NUM> samples) and with cutoff frequency = Fbit/<NUM> (moving average over <NUM> samples). The edge detector is a correlator with a step function with <NUM> samples per bit interval (<NUM> low, <NUM> high).

Following the Differential Manchester encoding, a transition is always guaranteed at the bit boundary. When a <NUM> is transmitted there is no other transition and the output of the edge detector will have two local maxima or minima separated by a full bit interval. When a <NUM> is transmitted there is also a transition in the middle of the bit interval and the output of the edge detector will have three local maxima or minima separated by half bit interval. When the signal is transformed into OOK the <NUM> will cause the output to be flat and the <NUM> will cause the output to have just one local maximum or minimum. To avoid bit slips and ensure synchronization, long sequences of <NUM> could be avoided. This can be obtained by bit stuffing techniques or by suitable encoding, such as adding an even parity bit every N bits, where N is an even number.

<FIG> are graphs illustrating signals associated with <FIG>, with interferents added into the signals, according to one embodiment. More particularly, graphs <NUM>-<NUM> of <FIG> correspond to graphs <NUM>-<NUM> of <FIG>, but with interferents included in the signals. The interferents distort the signals in the graphs <NUM>-<NUM>. The graphs <NUM>-<NUM> correspond to the graphs <NUM>-<NUM> of <FIG>, but with interferents added into the signals. The graphs <NUM>-<NUM> corresponds to the graphs <NUM>-<NUM>, after interferents have been added into the signals of <FIG>. Notably, the graphs <NUM>-<NUM> illustrate that the low-pass filter significantly reduces the effects of interferents, as the graphs <NUM>-<NUM> strongly match the graphs <NUM>-<NUM> but with small amounts of noise. So small amounts of noise will not prevent accurately the coating the data from the signals.

Returning to <FIG>, in one embodiment, the transmitting electronic device <NUM> is a wireless charging device. In this case, the carrier signal is configured to provide energy to the receiving electronic device <NUM>. For example, when the receiving electronic device <NUM> is placed adjacent to the transmitting electronic device <NUM>, the transmitting electronic device <NUM> outputs the carrier signal. The receiving electronic device <NUM> includes energy harvesting circuitry that harvests energy from the carrier signal. The carrier signal may also be termed a wireless charging signal in this case. The receiving electronic device <NUM> may generate a charging current from the carrier signal.

In one embodiment, the wireless charging circuitry operates in accordance with a Qi wireless charging standard. The Qi wireless charging circuitry outputs a charging field in a range between <NUM> and <NUM>, though other frequencies may be used as standards are adjusted or as differing applications call for other frequencies outside this range. Data can be encoded into the charging field with a lower frequency than the frequency of the charging field. The low-pass filter will effectively filter out effects of the higher frequency charging field when the coding data from the charging field. Other wireless charging standards can be utilized without departing from the scope of the present disclosure.

In one embodiment, the transmitting electronic device <NUM> and the receiving electronic device <NUM> are near field communication (NFC) devices. In particular, the transmitting electronic device <NUM> outputs an NFC carrier signal with interrogation data encoded into the carrier signal. The receiving electronic device <NUM> receives the carrier signal and decodes a carrier signal utilizing the low-pass filter as described previously. The receiving electronic device and the transmitting electronic device <NUM> can communicate with each other the NFC protocols. In one example, the NFC carrier signal has a frequency of <NUM>. However, other frequencies for the carrier signal can be utilized without departing from the scope of the present disclosure. Data is encoded into the carrier signal at a lower frequency than the frequency of the carrier signal. Accordingly, the low-pass filter can effectively reject effects of the higher frequency NFC carrier signal when the coding data from the NFC carrier signal. The receiving electronic device <NUM> may include an active NFC device or a passive NFC device.

While <FIG> as illustrated a transmitting electronic device <NUM> and the receiving electronic device <NUM>, in practice, the receiving electronic device may also transmit data to the transmitting electronic device <NUM>. Accordingly, the transmitting electronic device <NUM> and the receiving electronic device may each both transmit and receive data from the other. Accordingly, the transmitting electronic device <NUM> and the receiving electronic device <NUM> may be termed first and second electronic devices.

<FIG> is a block diagram of a wireless communication system <NUM>, according to one embodiment. The wireless communication system <NUM> includes an electronic device <NUM> and a wireless charging device <NUM>. The wireless charging device is one example of a transmitting electronic device <NUM> of <FIG>. The electronic device <NUM> is one example of a receiving electronic device <NUM> of <FIG>.

The transmitting electronic device <NUM> includes a transceiver <NUM>, a control system <NUM>, a power source <NUM>, and a charging bay <NUM>. The control system <NUM> includes control logic <NUM>. The components of the transmitting electronic device <NUM> to cooperate together to provide wireless communication and separate wireless charging.

The transceiver <NUM> enables the wireless charging device <NUM> to transmit signals and to receive signals. The transceiver <NUM> can include one or more antennas for transmitting NFC signals and for receiving NFC signals. The transceiver <NUM> can include additional circuitry for enabling the transceiver <NUM> to transmit signals including interrogation signals, carrier signals, and other types of signals. The transceiver <NUM> can include additional circuitry for enabling the transceiver <NUM> to receive and process signals including interrogation signals and other types of signals from the electronic device <NUM>.

The control system <NUM> includes control circuitry for controlling the function of the wireless charging device <NUM>. The control system <NUM> controls the operation of the transceiver <NUM>. The control system <NUM> controls the transmission of signals with the transceiver <NUM>. The control system <NUM> also controls the reception of signals with the transceiver <NUM>. The control system <NUM> can include processing resources, memory resources, and data transmission resources.

The control system <NUM> includes the control logic <NUM>. The control logic <NUM> can include instructions for operation of the control system <NUM>. The control logic <NUM> can include instructions protocols for performing the operations, processes, and methods executed by the wireless charging device <NUM>, including those described herein. The control logic <NUM> can correspond to software instructions stored in a memory of the wireless charging device <NUM>.

The power source <NUM> provides power to the wireless charging device <NUM>. The power source <NUM> can include one or more of an internal battery, a wired power connection to an external power source, and a wireless power connection to an external power source.

The transceiver <NUM> selectively provides a wireless charging field to the electronic device <NUM>. The transceiver <NUM> includes one or more antennas. In one embodiment, the transceiver <NUM> operates in accordance with a Qi wireless charging standard. The Qi wireless charging circuitry outputs a charging field in a range between <NUM> and <NUM>. The transceiver <NUM> may also operate in accordance with charging protocols or standards other than Qi without departing from the scope of the present disclosure.

The transceiver <NUM> of the wireless charging device <NUM> can be controlled by the control logic <NUM> of the control system <NUM>. The RF transceiver selectively outputs the wireless charging field based on the types of NFC devices present as detected by the control system <NUM>.

The charging bay <NUM> includes a physical area on which an electronic device <NUM> can be positioned in order to receive wireless charging signals from the wireless charging device <NUM>. When an electronic device <NUM> is positioned on the charging bay <NUM>, the wireless charging device <NUM> detects the electronic device <NUM> and causes the transceiver <NUM> to begin outputting the wireless charging field.

The electronic device <NUM> includes an antenna coil <NUM>, a controller <NUM>, energy harvesting circuitry <NUM>, and a memory <NUM>. The antenna coil <NUM> includes one or more antennas and other circuitry for receiving signals from the wireless charging device <NUM> and for providing signals to the wireless charging device <NUM>. Accordingly, antenna coil <NUM> may be part of a transceiver of the electronic device <NUM>.

The controller <NUM> controls the operation of the antenna coil <NUM>. The controller <NUM> controls the modulation signals output from the antenna coil <NUM> responsive to interrogation signals received from the wireless charging device <NUM>. The controller <NUM> may control modulation of an impedance of the antenna coil <NUM>. The memory <NUM> stores identification data related to the electronic device <NUM>.

When the antenna coil <NUM> receives signals from the wireless charging device <NUM>, the energy harvesting circuitry <NUM> harvests energy from the signals. If the electronic device <NUM> is an active electronic device, then the electronic device <NUM> may utilize the energy harvested from the wireless charging signal to provide a charging current to a battery of the electronic device <NUM>. If the electronic device <NUM> is a passive electronic device, the energy harvested from the wireless charging signal may be utilized to power the other components of the electronic device <NUM>.

In one embodiment, when the antenna coil <NUM> receives the wireless charging signal, the wireless charging signal is passed to both the energy harvesting circuitry <NUM> and to the low-pass filter <NUM> in parallel to each other. The low-pass filter <NUM> filters out higher frequency signals associated with higher bit rate or bandwidth data values encoding into the wireless charging signal, such as binary <NUM> in the case of differential Manchester encoding. Accordingly, the low-pass filter <NUM> effectively transforms the ASK modulated wireless charging signal to an OOK modulated wireless charging signal. The controller or other receiving circuitry can then decode the data from the OOK signal, as described previously. The electronic device <NUM> may include other circuitry without departing from the scope of the present disclosure.

<FIG> is a flow diagram of a method <NUM> for operating an electronic device, according to one embodiment. The method <NUM> can utilize components, systems, and processes described in relation to <FIG>. At <NUM>, the method <NUM> includes receiving, with a first electronic device, a carrier signal transmitted from a second electronic device and including data encoded with an amplitude-shift keying scheme. At <NUM>, the method <NUM> includes generating, from the carrier signal with the first electronic device, an on-off keying signal by passing the carrier signal through a low-pass filter. At <NUM>, the method <NUM> includes decoding, with the first electronic device, the data from the on-off keying signal.

In one embodiment, a method includes receiving, with an electronic device, a carrier signal encoded with data and harvesting energy from the carrier signal with the first electronic device. The method includes passing the carrier signal through a low-pass filter having a cutoff frequency between a first frequency associated with data values of a first type and a second frequency associated with data values of a second type and decoding the data from the carrier signal after passing the carrier signal through the low-pass filter.

In one embodiment, a method includes receiving, with a first electronic device, a carrier signal transmitted from a second electronic device and including data encoded with an amplitude-shift keying scheme. The method includes generating, from the carrier signal with the first electronic device, an on-off keying signal by passing the carrier signal through a low-pass filter and decoding, with the first electronic device, the data from the on-off keying signal.

In one embodiment, an electronic device includes an antenna configured to receive, from a transmitting electronic device, a carrier signal including data encoded with an amplitude-shift keying scheme. The electronic device includes a low-pass filter configured to receive the carrier signal and to generate an on-off keying signal from the carrier signal. The electronic device includes a controller configured to decode the data from the on-off keying signal.

Claim 1:
A method, comprising:
receiving, with a first electronic device, an ASK modulated carrier signal transmitted from a second electronic device and including data encoded with an amplitude-shift keying scheme;
demodulating said ASK modulated carrier signal, resulting in a demodulated signal in which data having a first binary state have a lower frequency than data having a second binary state;
applying an edge detector to said demodulated signal;
applying a low-pass filter to the signal provided by said edge detector, resulting in an on-off keying signal in which:
data having said first binary state are represented by durations of nonzero amplitude; and;
data having said second binary state are represented by durations of substantially zero amplitude.