Continuous synchronization signaling for crystal-less communication links

​An apparatus comprising:

• a first physical layer device, the first physical layer device comprising:
• a receiver configured to receive a continuous synchronization signal from a second physical layer device, wherein the continuous synchronization signal omits quiet periods between successive synchronization transmissions;
• timing recovery circuitry configured to extract clock information from the continuous synchronization signal and to derive timing from the continuous synchronization signal to compensate for a frequency offset relative to the second physical layer device, wherein the timing recovery circuitry is configured to perform clock extraction during both synchronization and data transmission phases;
• and
• a transmitter configured to transmit, using timing derived from the extracted clock information, a synchronization response to the second physical layer device.

​An apparatus comprising:

• a transmitter configured to transmit a continuous synchronization signal to a first physical layer device, wherein the continuous synchronization signal omits quiet periods between successive synchronization transmissions;
• a receiver configured to receive a synchronization response from the first physical layer device;
• and
• a controller configured to cause transmission of an acknowledgment indication to the first physical layer device upon successful receipt of the synchronization response, the acknowledgment indication confirming to the first physical layer device that the synchronization response was received.