A2B Comparision
coherent-receiver.com audio bus (CR-AB) and Analog Devices A2B bus are bidirectional, digital, multichannel audio buses that capable of transporting I2S/TDM/PDM data, I2C, SPI control information, along with clock and power using external cables over distances up to 15 meters. Following section provides the comparison between these technologies:
| Criteria | A2B | CR-AB |
|---|---|---|
| Intelligence in slave node | custom Analog Devices A2B transceiver on each slave node | no custom chips required |
| Synchronization and latency | single synchronization, low and deterministic latency. Master generates clock, synchronization and framing for all nodes. All nodes are sampled synchronously. | single synchronization, low and determenistic latency. Master generates clock, synchronization and framing for all nodes. All nodes are sampled synchronously and send to the host simultaneously (interleaved data stream). No packet collision. |
| Bus protocol | Proprietary ADI bus protocol | standard audio transmission protocols |
| Host connection | A2B transceiver can connect directly to general-purpose digital signal processor (DSPs), field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs) | USB3.0 and processor/GPU processing |
| Legacy hardware support (I2S, TDM, PDM) without additional components | No, ADI transceiver required | Yes, on the PCB implementation |
| Power supply | Bus powered | Bus powered |
| Cabling | Single differential wire pair | Category 5 cable (Cat 5) |
| Topology | multi-node protocol with a single master and up to ten slaves connected in a daisy-chain topology | single master and up to 62 slaves per USB port in a star topology |
| Maximum Distance | up to 40 m (15 m between two nodes) | up to 10 m |
| Maximum Sample rate | up to 192 kHz | up to 768 kHz |
| Resolution | up to 32 bit | up to 32 bit |
| Max Number of channels | 32 downstream and 32 upstream channels | 31 downstream and 31 upstream channels (or 62 downstream or 62 upstream channels in case of single direction) without multiple USB synchronisation. 30 downstream and 30 upstream channels (or 60 downstream or 60 upstream channels in case of single direction) with multiple USB synchronisation. The number of channels can be increased if TDM is used. Multi-master synchronization is possible and supports synchronized topologies with an unlimited number of channels |
| I2C support | Yes | Yes |
| GPIO support | Yes | Yes, using an I2C register |
| PCB Implementation | Not suitable | Yes, ideal for arrays/beamforming |
| Applications | Automotive | No restrictions |
Comparison with A2B
coherent-receiver.com audio bus (CR-AB) and Analog Devices A2B bus are bidirectional, digital, multichannel audio buses that capable of transporting I2S/TDM/PDM data, I2C, SPI control information, along with clock and power using external cables over distances up to 15 meters. Following section provides the comparison between these technologies.
Intelligence in slave node
- A2B: custom Analog Devices A2B transceiver on each slave node
- CR-AB: no custom chips required
Synchronization and latency
- A2B: single synchronization, low and deterministic latency. Master generates clock, synchronization and framing for all nodes. All nodes are sampled synchronously
- CR-AB: single synchronization, low and determenistic latency. Master generates clock, synchronization and framing for all nodes. All nodes are sampled synchronously and send to the host simultaneously (interleaved data stream). No packet collision
Bus protocol
- A2B: proprietary ADI bus protocol
- CR-AB: standard audio transmission protocols
Host connection
- A2B: A2B transceiver can connect directly to general-purpose digital signal processor (DSPs), field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs)
- CR-AB: USB3.0 and processor/GPU processing
Legacy hardware support (I2S, TDM, PDM) without additional components
- A2B: no, ADI transceiver required
- CR-AB: yes, on the PCB implementation
Power supply
- A2B: bus powered
- CR-AB: bus powered
Cabling
- A2B: single differential wire pair
- CR-AB: category 5 cable (Cat 5)
Topology
- A2B: multi-node protocol with a single master and up to ten slaves connected in a daisy-chain topology
- CR-AB: single master and up to 62 slaves per USB port in a star topology
Maximum distance
- A2B: up to 40 m (15 m between two nodes)
- CR-AB: up to 10 m
Maximum sample rate
- A2B: up to 192 kHz
- CR-AB: up to 768 kHz
Resolution
- A2B: up to 32 bit
- CR-AB: up to 32 bit
Max number of channels
- A2B: 32 downstream and 32 upstream channels
- CR-AB: 31 downstream and 31 upstream channels (or 62 downstream or 62 upstream channels in case of single direction) without multiple USB synchronisation. 30 downstream and 30 upstream channels (or 60 downstream or 60 upstream channels in case of single direction) with multiple USB synchronisation. The number of channels can be increased if TDM is used. Multi-master synchronization is possible and supports synchronized topologies with an unlimited number of channels
I2C support
- A2B: yes
- CR-AB: yes
GPIO support
- A2B: yes
- CR-AB: yes, using an I2C register
PCB implementation
- A2B: not suitable
- CR-AB: yes, ideal for arrays/beamforming
Applications
- A2B: automotive
- CR-AB: no restrictions