Methods, apparatus, systems, and articles of manufacture to implement a third-order signal scrambler are disclosed. An example apparatus includes a controlled scramble generator to generate a controlled random sequence based on one or more subcarriers and a random pulse sequence, the random pulse sequence based on an output of a random number generator processed by a multi-order sinusoidal noise function. The example apparatus further includes a sequence modifier to form an output sequence by combining a source sequence with the controlled random sequence, the controlled random sequence to modify a characteristic of the source sequence in a frequency domain.

Methods, apparatus, systems, and articles of manufacture to implement a third-order signal scrambler are disclosed. An example apparatus includes a controlled scramble generator to generate a controlled random sequence based on one or more subcarriers and a random pulse sequence, the random pulse sequence based on an output of a random number generator processed by a multi-order sinusoidal noise function. The example apparatus further includes a sequence modifier to form an output sequence by combining a source sequence with the controlled random sequence, the controlled random sequence to modify a characteristic of the source sequence in a frequency domain.

An environmental sound generating apparatus generates an environmental sound signal representing an environmental sound that forms sound environment by being emitted. The environmental sound has at least one chain of phonemes constituted of individual phonemes which sound-emission start timings as one of attributes thereof are sequentially shifted. A plurality of subgroups are prepared each formed by combining individual plural pitches from pitches constituting a primary pitch group that is a group of phonemes musically treated as consonances if sounded simultaneously. One of the plurality of subgroups selected at random is set to each of the sections of the chain of phonemes, and each of the individual phonemes of each section of the chain of phonemes is set to a pitch selected at random from the plural pitches constituting the selected subgroup to attain hypersonic effects.

In general, the subject matter described in this specification can be embodied in methods, systems, and program products for identifying data that is designated for wireless transmission to a remote computing device. A digital signal that encodes the data for transmission across a band of radio frequency channels is generated. Multiple radio frequency channels in the band that are available are determined. The digital signal is filtered to substantially reduce a power level of the digital signal at frequencies that correspond to channels in the band that have not been determined to be available. The filtered digital signal is converted to an analog signal. The analog signal is provided to an analog transmitter that isolates the band of channels to generate an isolated analog signal and that wirelessly transmits the isolated analog signal over the multiple available channels using one or more antennas.

Methods, systems, and devices for wireless communications are described. A first wireless device may communicate, with a second wireless device, a first set of messages of a first message type that are acknowledged according to an acknowledgement procedure. The first wireless device, the second wireless device, or both may select a first subset of messages of the first plurality of messages and a first subset of bits from each message of the first subset of messages based on the first set of messages being acknowledged and according to a sampling configuration common to both the first wireless device and the second wireless device. The first wireless device, the second wireless device, or both may generate a key using bit values of the first subset of bits from each message of the first subset of messages, encoding a message using the key, and communicate the encoded message.

Aspects of the present disclosure describe scrambling of information for wireless communications to prevent deciphering or altering by unintended recipients. An example method may include generating, by a first device, a scrambling key based on at least one of a freshness parameter or a private key. The private key is known by the first device and a second device. The method also includes scrambling a payload based on the scrambling key at a physical layer. A packet includes the payload for wireless transmission from the first device to the second device via a shared channel.

Managing digital workflows based on events involving digital representations of physical assets in enterprise asset management (EAM) systems. Events are detected and workflows are generated based on information in the digital representations and one or more digital libraries having resources for the digital representations.

A method includes identifying, by an electronic device, one or more segments within a first audio recording that includes one or more non-speech segments and one or more speech segments. The method also includes generating, by the electronic device, one or more synthetic speech segments that include natural speech audio characteristics and that preserve one or more non-private features of the one or more speech segments. The method also includes generating, by the electronic device, an obfuscated audio recording by replacing the one or more speech segments with the one or more synthetic speech segments while maintaining the one or more non-speech segments, wherein the one or more synthetic speech segments prevent recognition of some content of the obfuscated audio recording.

Methods, systems, and devices for channelizing a wideband waveform for transmission on a spectral band comprising unavailable channel segments are described. Generally, the described techniques provide for transmitting and receiving wideband waveforms when channels of a system bandwidth are unavailable for transmission. A transmitter may separate a first wideband signal into segments, with each segment a bandwidth corresponding to a channel of the system bandwidth, and may map the segments to the available channels. The transmitter may combine the mapped segments into a second wideband waveform and transmit the second wideband waveform using the available channels. A receiver may receive a first wideband signal waveform and may separate the first wideband signal waveform into segments, de-map the segments and combine the de-mapped segments into a second wideband waveform for demodulation. The techniques may be used to transmit and receive wideband waveforms over tactical data links.

A method, for preventing the intelligible voice recording is provided. The voice of a subject or interlocutor is recorded for a given time interval thereby providing a voice recording. The voice recording is cut into shorter time interval segments thereby providing a set of voice recording segments. The set of voice recording segments is mixed in a randomly rearranged order. The mixed set of voice recording segments is spliced into a single randomly mixed voice recording. Emitting the randomly mixed voice recording during speaking of the subject or interlocutor prevents the intelligible recording of the voice of the subject or interlocutor.