Glossary

SPARK Microsystems SDK: The piece of software used to develop an application based on SPARK Microsystems Ultra-Wideband wireless technology. It includes various components such as application examples, board support packages, drivers and libraries.
SR1000 Series: The SPARK Microsystems SR1000 Series includes all SR10XX transceivers currently available.
SR1100 Series: The SPARK Microsystems SR1100 Series includes all SR11XX transceivers currently available.

Audio Core Glossary

ADPCM: Adaptive Differential Pulse-Code Modulation is an audio compression algorithm that can achieve a compression factor of 4 (i.e., 16-bit samples become 4-bit samples). See the Audio Compression section for more details.
Aliasing: Distortion caused by high frequency content (higher than the Nyquist frequency) folding back into the original signal. This is usually solved by proper low-pass filtering before sampling.
Audio API: The Audio Core’s set of public functions meant to be called by an audio application. See the Audio Core API section for more details.
Audio Channel: A set of audio samples that represent a single stream of recorded sound.
Audio Consumer: An endpoint used to consume audio samples (consumer) in an audio pipeline. See the Audio Endpoint section for more details.
Audio Core: SPARK Microsystems’ audio library. See the Audio Core section for more details.
Audio Device: A physical device that makes use of the SPARK Microsystems Audio Core.
Audio Endpoint: Occupies both ends of an audio pipeline. It can produce and/or consume audio samples. It implements an endpoint interface. Common examples are a hardware audio codec and the SPARK Wireless Core. See the Audio Endpoint section for more details.
Audio Fallback: A mode of operation where the audio samples are modified on the fly to adapt to a bad wireless link. Examples of fallback processing is the ADPCM compression. See the Audio Fallback section for more details.
Audio Frame: The part of the payload that contains one audio samples per channel. If there is only one channel (Mono sound) a frame is simply a single sample. If the stream is stereo, each frame consists of two samples, etc.
Audio Header: The part of the audio packet that contains audio protocol information. See the Audio Header section for more details.
Audio Packet: The combination of the audio header and the audio payload.
Audio Payload: The part of the audio packet that contains audio frames.
Audio Pipeline: The path the audio samples will go through from one endpoint to another. An audio pipeline is a concept that is local to an audio device. See the Audio Pipeline section for more details.
Audio Processing: Operations applied on audio samples to modify them. Examples are compression/decompression and sampling rate conversion. See the Audio Processing Stage section for more details.
Audio Producer: An endpoint used to produce audio samples (producer) in an audio pipeline. See the Audio Endpoint section for more details.
Audio Sample: A single sample represents the amplitude of one channel of sound at a certain point in time.
Audio Sample Accumulator: The process of accumulating a higher number of samples per packet before sending them to be compressed or packed by the fallback processing stages. The effect of this process is that the retransmission rate will increase which in turn increases the reliability of the wireless audio stream.
Audio Sample Bit Depth: The number of bits of information in each sample. If the Sample size is bigger than the sample bit depth, only the lowest significant bits are useful, the rest are padding.
Audio Sample Size: The number of bits required to store a single sample.
Audio Scaling: The process of increasing or reducing an audio sample bit depth.
Audio Stream: A general term to talk about the data the audio represents. For example, a microphone audio stream or the audio stream from an audio streaming service.
CDC: Clock Drift Compensation is a sort of audio processing that compensates the difference between the audio clocks of two audio devices using resampling for gradually creating and dropping samples. See the Clock Drift Compensation section for more details.
Decimation: The process of reducing the sampling rate by first low-pass filtering then throwing away samples.
Downsampling: The process of reducing the sampling rate without low-pass filtering. Can be loosely used as a synonym of decimation.
Interpolation: The process of interpolation is a type of estimation, a method of constructing (finding) new data points based on the range of a discrete set of known data points.
Linear Interpolation: The process of interpolating a new data point by tracing a line between two points. This process is very simple, but not very precise when getting close to the nyquist frequency.
Packing: The process of aligning audio samples to their bit depth instead of aligning to the CPU word size. (e.g. 24-bit audio is aligned in a 32-bit word when processed, but can be packed to 24-bit in an audio packet sent over-the-air to save memory space.)
Resampling: The process of changing the sampling rate of a set of samples. New samples will be estimated using an interpolation method.
SAC: SPARK Audio Core.
SRC: Sampling Rate Conversion is a sort of audio processing that increases or decreases the sampling rate of already sampled audio samples through interpolation and decimation respectively. See the Sampling Rate Converter section for more details.
Unpacking: The process of expanding audio samples from their packed bit-depth representation into a CPU word size for processing. (e.g. 24-bit audio samples received in a compact 24-bit over-the-air packet are unpacked into 32-bit words, with proper sign extension and alignment.)
Upsampling: The process of increasing the sampling rate without low-pass filtering. Can be loosely used as a synonym of interpolation.

Wireless Core Glossary

ACK: Acknowledgment. A short frame sent by the receiver to confirm successful reception of a data frame. See ARQ for more context.
ARQ: Automatic repeat request is an error-control method that uses acknowledges and retransmissions.
Auto-Reply: Auto-Reply is a mechanism which allows the transceiver to automatically send a frame with minimal delay after a reception. Not to be confused with Auto-Reply Timeslots which make use of the auto-reply mechanism to send a payload.
Beacon: A Beacon is a transmitted (generally broadcasted) frame for the sole purpose of synchronization between devices of a TDMA network. See the Sync Timeslot (Beacon) section for more details.
CCA: Clear Channel Assessment is a mechanism for determining whether the medium is idle or not. See the Clear Channel Assessment (CCA) section for more details.
CCA Contention: CCA Contention (channel access contention) is a form of contention for the same channel between transmitters belonging to different, concurrent networks at the same time. The Wireless Core arbitrates it with CCA: a transmitter senses the channel and defers (or forces) its transmission when another network is already using it. See the Clear Channel Assessment (CCA) and Concurrency sections for more details.
Channel: A Channel regroups a set of parameters required to configure a transmission such as frequency, pulses and pre-amplifier gain. See the Channel section for more details.
Concurrency: Concurrency is a generic term that abstracts all the mechanisms required to enable the operation of multiple independent networks concurrently. See the Concurrency section for more details.
Connection: A Connection defines a unidirectional communication link between two devices. See the Connection section for more details.
Connection Priority Contention: Connection Priority Contention is a form of contention between multiple connections of the same device (a single transmitter) that are assigned to the same timeslot. Only one connection can transmit per timeslot, so the Wireless Core arbitrates by Connection Priority: the highest-priority connection that has data to send wins the timeslot and the lower-priority connections defer to a later one. Unlike Timeslot Access Contention, this involves a single known transmitter, so it is fully supported.
Contention: Contention refers to two or more parties competing for the same shared transmission resource at the same time; resolving it requires some form of arbitration.
Coordinator: This is the role of the device on which all other devices synchronize. The Coordinator will generally be the device sending the Beacon.
DDCM: Distributed De-synchronization Concurrency Mechanism is an algorithm that aims to optimize the air-time allocation of concurrent networks by de-synchronizing the coordinator of an network from other networks.
Dual Radio: This is a special mode of operation allowing a device to use two transceivers for reception instead of one. This is generally used to extend RF coverage. See the Dual Radio section for more details.
FDMA: Frequency-Division Multiple Access is possible to achieve by ensuring that simultaneous transmissions use non-overlapping frequencies.
FEC: Forward Error Correction is directly supported by the transceiver and increases robustness of transmissions at the cost of frame size inflation. See the Forward Error Correction (FEC) Ratio section for more details.
Frame: A Frame represents the complete bitstream sent over-the-air by the transceiver. See the Frame Structure section for details.
Inter-Symbol Interference: Inter-Symbol Interference (ISI) refers to the distortion or overlap between symbols due to multipath propagation.
IRQ: Interrupt Request. Radio hardware interrupt raised at the end of a TX+ACK exchange to trigger post-slot MAC-layer processing.
MAC: Medium Access Control. The protocol layer responsible for scheduling frame transmissions on the shared radio medium, including timeslot management, CCA, and retransmissions.
Modulation: The transceiver supports various Modulation strategies which defines how to shape the RF energy to represent bits. See the Modulation section for more details.
Network: A Network defines a group of intercommunicating devices. In a TDMA network, those devices will know each other in advance and share the same schedule.
Node: A Node corresponds to any device part of a SPARK wireless network. A Node can also take on the role of the Coordinator on which all other nodes of the network will synchronize.
NVM: Non Volatile Memory
OTA: Over-The-Air. Any exchange or transmission that occurs on the wireless link, as opposed to wired paths inside a device.
PER: Packet Error Rate. Fraction of transmitted packets that fail to be received correctly, either lost or received corrupted. Directly drives the ARQ retransmission rate.
PHY: Physical layer. The lowest layer of the wireless stack, responsible for symbol encoding, modulation, and radio hardware control.
Preamble: The Preamble is an energy pattern all frames start with. The receiver will use this energy pattern to adjust its reception gain in preparation of the following frame reception. See the Frame Structure section for more details.
Pulse: Pulses are energy bursts that compose a symbol. More pulses or wider pulses means more energy.
RDO: Random Datarate Offset. A small per-slot timing jitter injected on purpose to spread the CCA attempts of concurrent networks that would otherwise transmit in phase. See the Random Datarate Offset Protocol (RDO) section for more details.
ReTX: The Retransmissions are transmissions of frames which contains an already sent payload, but was not ACKed. Retransmissions are essential to maximize the robustness of an RF link between 2 devices. See the Retransmission Margin section for more details.
ReTX Margin: The Retransmission Margin is the portion of the wireless link throughput that is free to use for retransmissions. For more details, see the Retransmission Margin section.
RF: Radio Frequency. The band of electromagnetic frequencies used for wireless transmission.
RX: Receive or Reception. Refers to the direction in which a device receives a frame from another device on the wireless link.
Schedule: Implicitly referring to a TDMA Schedule, this defines the timeslots in which devices can transmit or receive. See the Schedule section for more details.
SFD: Start of Frame Delimiter. Following the preamble, the SFD is a bit pattern that allows the receiver to synchronize on the incoming frame data. See the Frame Structure section for more details.
SWC: SPARK Wireless Core.
Symbol: A Symbol refers to the pulse pattern which represents a bit over-the-air.
Synchronization: Synchronization refers to the Nodes adjusting their timing to match the Coordinator’s own. See the Synchronization Methods section for more details.
TDMA: Time-Division Multiple Access is a method by which time is divided into pre-determined periods (also called timeslots) allocated for specific transmissions. See the Time Division Multiple Access section for more details.
Throttling: This mechanism allows the user to reduce the wireless link throughput on-the-fly by disabling certain timeslots. Useful for power management. See the Link Throttling section for more details.
Timeslot: A Timeslot is a short period of time dedicated for a specific transmission. Timeslots compose a schedule. See the Time Division Multiple Access section for more details.
Timeslot Access Contention: Timeslot Access Contention is a form of contention where two or more separate devices (distinct transmitters) attempt to transmit in the same timeslot on the same channel at the same time. Resolving it would require an arbitration mechanism such as CCA. The Wireless Core does not support timeslot access contention: because each timeslot has a single transmitter, the receiver cannot identify which device transmitted, so multiple devices are never allowed to contend for one timeslot. This is distinct from Connection Priority, which arbitrates among multiple connections of the same device sharing a timeslot.
TTL: Time-to-Live is a mechanism allowing the user to define a maximum retransmission time or a maximum retransmission count. Past any of these limits, frames will be dropped by the transmitter.
TX: Transmit or Transmission. Refers to the direction in which a device sends a frame to another device on the wireless link.
Ultra-Wideband: Ultra-Wideband is a radio technology that uses short pulses to communicate. It allows very low power data transmission.
Wireless Core: The Wireless Core is a software module which enables users to create a wireless link by using its API. See the Wireless Core section for more details.
Wireless Core API: This is the main public API that the user can use to create applications with the SPARK Ultra-Wideband transceivers. See the Wireless Core API section for more details.