The core of Kandou’s innovative technology is a novel signaling method called Chord signaling™ which is based on a very general signaling and modulation theory centered around efficient circuit implementations. The theory is at the intersection of electronics, information theory, discrete mathematics and algorithm design. Chord signaling™ transmits correlated signals across multiple wires, the same way that differential signaling sends correlated signals across two wires. Unlike many other signaling methods like ternary signaling or PAM-4 signaling, Chord signaling™ exhibits the same performance with regard to intersymbol-interference as differential NRZ at a lower clock frequency.
Central to Chord signaling™ is the concept of a chordal code. One of the
components of a chordal code is a set of vectors of the same length as the
number of wires in the underlying interface, called the codebook. The vectors
in a codebook correspond to values that are simultaneously
transmitted on the wires. For example,
for differential signaling,
the codebook consists of the two-dimensional
(-1,+1), meaning that the values on
the two wires in the interface are complementary. The second, equally important,
components of a chordal code is a matched set of "multi-input comparators."
As the name suggests, these vectors correspond to comparators that compare a
linear combination of the values on some wires against another such linear
More information on Chord signaling™ can be found here
To meet the stringent requirements of very high-speed SerDes links, Kandou has developed various methods, circuits, and topologies matched to Chord Signaling for tasks such as
- Coded equalization
- Matched low power CTLE/FIR/DFE
- Crosstalk, SSO, EMI noise reduction
- Power reduction (line power and receiver)
- Mismatch tolerance
- Efficient CDR
- Efficient board routing
- Clock embedding
- Larger interfaces (through efficient coding algorithms)
- Area minimization
- Pin reduction
- ….and more
Chord signaling™ is well suited to mobile and networking applications where traditional interfaces like PAM-4 and NRZ are approaching or have reached their technical limits.
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