# US 2019/0379474 A1 · Shared Communication Channel That Interleaves 1 PPS Signals and Messaging > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0379474 A1 - Document ID: US20190379474A1 - Status: Published application - Kind: A1 - Application number: 16/235,232 - Filed: 2018-12-28 - Published: 2019-12-12 - Earliest claimed: 2018-06-11 - Assignees: Skyworks Solutions, Inc. - Applicants: Silicon Laboratories Inc. - Inventors: Robert P. Coulter - Web page: https://patentgrep.com/patent/US20190379474A1 ## CPC - H04J 3/0667: {Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays (arrangements for monitoring round trip delays in packet switching networks H04L43/0864)} - H04J 3/0632: {Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] (queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56)} - H04J 3/0673: {using intermediate nodes, e.g. modification of a received timestamp before further transmission to the next packet node, e.g. including internal delay time or residence time into the packet} - H04J 3/0688: {Change of the master or reference, e.g. take-over or failure of the master} - H04J 3/0697: {Synchronisation in a packet node} - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) ## Abstract A shared bus time interleaves 1 PPS signal and control and coordination information between a primary timing source and line cards that need to be synchronized using the 1 PPS signals. The shared bus utilizes 1 second frames divided into time slots. The 1 PPS signals are interleaved at predetermined locations in the frame so the delays introduced by interleaving the 1 PPS data in time can be precisely removed. While the bus is not being used for 1 PPS signals, the bus is available to send control and coordination information between the line cards and the primary timing source, avoiding the use of another system and increasing utilization of an available communication path. ## Claims ### Claim 1 A method comprising: sending a first 1 pulse per second (1 PPS) signal over a time information bus from a primary timing source to a first line card during a first portion of a one second interval; sending information from the first line card over the time information bus to the primary timing source during a second portion of the one second interval; sending information from a second line card to the primary timing source over the time information bus during a third portion of the one second interval. ### Claim 2 (depends on 1) The method as recited in claim 1 further comprising: sending the first 1 pulse per second (1 PPS) signal over the time information bus from the primary timing source to the second line card during the first portion of the one second interval. ### Claim 3 (depends on 1) The method as recited in claim 1 further comprising: using the time information bus to send a message indicating a change from the primary timing source to another primary timing source. ### Claim 4 (depends on 1) The method as recited in claim 1 further comprising: sending first time stamp information from the first line card to the primary timing source over the time information bus, the first time stamp information indicative of a first time a first timing message from the primary timing source is received; sending second time stamp information from the second line card to the primary timing source over the time information bus, the second time stamp information indicative of a second time a second timing message from the primary timing source is received by the second line card. ### Claim 5 (depends on 1) The method as recited in claim 1 further comprising: sending a clock signal from a timing card over a clock signal line to the first and second line cards, the clock signal being synchronous with the first 1 PPS signal. ### Claim 6 (depends on 1) The method as recited in claim 1 further comprising: sending a second 1 pulse per second (1 PPS) signal over the time information bus from the primary timing source to the second line card during a fourth portion of the one second interval. ### Claim 7 (depends on 6) The method as recited in claim 6: wherein the one second interval comprises a frame made up of a plurality of time slots and the first portion of the one second interval is a first time slot in the frame; wherein the second portion of the one second interval is a second time slot in the frame; wherein the third portion of the one second interval is a third time slot in the frame and wherein the fourth portion of the one second interval is a fourth time slot in the frame. ### Claim 8 (depends on 7) The method as recited in claim 7 wherein the second time slot is assigned to a location in the frame based on a first line card identification associated with the first line card and the third time slot is assigned another location in the frame based on a second line card identification associated with the second line card. ### Claim 9 (depends on 7) The method as recited in claim 7 further comprising: sending the first 1 PPS signal at a first predetermined location with respect to a beginning of the first time slot; and sending the second 1 PPS signal at a second predetermined location with respect to the beginning of the fourth time slot. ### Claim 10 (depends on 7) The method as recited in claim 7 wherein a first plurality of time slots in the frame, including the first and fourth time slots, are utilized for transmissions by the primary timing source to respective ones of a plurality of line cards, including the first and second line cards, and a second plurality of time slots in the frame, including the second and third time slots, are utilized for transmission by respective ones of the plurality of line cards. ### Claim 11 (depends on 1) The method as recited in claim 1 further comprising: sending a plurality of 1 pulse per second (1 PPS) signals, including the first 1 PPS signal, over the time information bus from the primary timing source to a respective plurality of line cards including the first line card during a fifth portion of the one second interval, the fifth portion being a contiguous portion and including the first portion. ### Claim 12 An apparatus comprising: a first line card; a primary timing source coupled to a bidirectional time information bus and configured to send a first 1 pulse per second (1 PPS) signal over the bidirectional time information bus to the first line card during a first portion of a one second interval on the bidirectional time information bus; wherein the first line card is configured to send information from the first line card to the primary timing source over the bidirectional time information bus during a second portion of the one second interval; and a second line card configured to send information from the second line card to the primary timing source over the bidirectional time information bus during a third portion of the one second interval. ### Claim 13 (depends on 12) The apparatus as recited in claim 12 wherein the second line card is configured to receive the first 1 pulse per second (1 PPS) signal sent over the bidirectional time information bus from the primary timing source to the second line card during the first portion of the one second interval. ### Claim 14 (depends on 12) The apparatus as recited in claim 12 wherein the primary timing source is configured to send a second 1 pulse per second (1 PPS) signal over the bidirectional time information bus to the second line card during a fourth portion of the one second interval. ### Claim 15 (depends on 14) The apparatus as recited in claim 14, wherein the one second interval comprises a frame having a plurality of time slots and the first portion of the one second interval is a first time slot in the frame; wherein the second portion of the one second interval is a second time slot in the frame; wherein the third portion of the one second interval is a third time slot in the frame; and wherein the fourth portion of the one second interval is a fourth time slot in the frame. ### Claim 16 (depends on 15) The apparatus as recited in claim 15 wherein the second time slot is assigned to a location in the frame based on a first line card identification associated with the first line card and the third time slot is assigned to another location in the frame based on a second line card identification associated with the second line card. ### Claim 17 (depends on 15) The apparatus as recited in claim 15, wherein the primary timing source is further configured to send the first 1 PPS signal during a first portion of the first time slot and to send information to the first line card during a second portion of the first time slot. ### Claim 18 (depends on 15) The apparatus as recited in claim 15, wherein the first line card is configured to send first time stamp information from to the primary timing source over the bidirectional time information bus during the second time slot, the first time stamp information indicative of a first time a first timing message from the primary timing source is received; wherein the second line card is configured to send second time stamp information to the primary timing source over the bidirectional time information bus during the fourth time slot, the second time stamp information indicative of a second time a second timing message from the primary timing source is received by the second line card. ### Claim 19 (depends on 15) The apparatus as recited in claim 15 further comprising: wherein the primary timing source is configured to send the first 1 PPS signal at a first predetermined location with respect to a beginning of the first time slot; and wherein the primary timing source is configured to send the second 1 PPS signal at a second predetermined location with respect to the beginning of the fourth time slot. ### Claim 20 (depends on 15) The apparatus as recited in claim 15 further comprising: a timing card coupled to send a clock signal to the first and second line cards over a clock signal line; and wherein the clock signal is synchronized with the first 1 PPS signal. ### Claim 21 (depends on 20) The apparatus as recited in claim 20 wherein the timing card is the primary timing source.