Two or more modules communicate over a common control network including receiving by a message packet having data defined by a signal level at defined bit quanta of a bit, the defined bit quanta being less than every bit quanta of a bit, and the communication device samples bit quanta other than the defined bit quanta. The module receives signal disturbances and decodes the signal disturbances as having a value different from an expected value of the certain bit. In another form, the module uses a first counter based on a clock local to the communication device and a second counter having a higher sampling rate than the first counter. Here, the module receives over the control network a synchronizing portion of a message and counts clock ticks of the second counter over a portion of the message to determine a clock rate for a module that transmitted the message.

Two or more modules communicate over a common control network including receiving by a message packet having data defined by a signal level at defined bit quanta of a bit, the defined bit quanta being less than every bit quanta of a bit, and the communication device samples bit quanta other than the defined bit quanta. The module receives signal disturbances and decodes the signal disturbances as having a value different from an expected value of the certain bit. In another form, the module uses a first counter based on a clock local to the communication device and a second counter having a higher sampling rate than the first counter. Here, the module receives over the control network a synchronizing portion of a message and counts clock ticks of the second counter over a portion of the message to determine a clock rate for a module that transmitted the message.

Two or more modules communicate over a common control network including receiving by a message packet having data defined by a signal level at defined bit quanta of a bit, the defined bit quanta being less than every bit quanta of a bit, and the communication device samples bit quanta other than the defined bit quanta. The module receives signal disturbances and decodes the signal disturbances as having a value different from an expected value of the certain bit. In another form, the module uses a first counter based on a clock local to the communication device and a second counter having a higher sampling rate than the first counter. Here, the module receives over the control network a synchronizing portion of a message and counts clock ticks of the second counter over a portion of the message to determine a clock rate for a module that transmitted the message.

In one embodiment, a computer apparatus includes a first NIC including at least one network interface port to transfer data with a first packet-data network (PDN) including a master clock to provide a clock synchronization signal S1, a first physical hardware clock (PHC) to maintain a time value T1 responsively to S1, and a first clock controller to generate a clock synchronization signal S2 responsively to S1, S2 having a frequency set responsively to S1, and send S2 over a connection to a second NIC including at least one network interface port to transfer data with a second PDN, a second PHC, and a second clock controller to receive S2, update the second PHC with a time value T2 responsively to S2, send another clock synchronization signal to network nodes in the second PDN responsively to T2, the second NIC acting as a master clock in the second PDN.

A method of synchronizing master and slave nodes on a high-speed Ethernet connection includes sending a first plurality of synchronization pulse units from the master, receiving at the master a second plurality of synchronization pulse units sent by the slave in response to receipt of the first plurality of synchronization pulse units, monitoring at the master for receipt of a first synchronization pulse unit from the second plurality, having a predetermined characteristic, monitoring at the master for receipt of at least one further synchronization pulse unit, from the second plurality, having the predetermined characteristic, and recognizing receipt of the second plurality upon receipt of the first and at least one further synchronization pulse unit having the predetermined characteristic, where the first synchronization pulse unit and the at least one further synchronization pulse unit meet either a first temporal spacing condition or an integer multiple of the first temporal spacing condition.

Two or more modules communicate over a common control network including receiving by a message packet having data defined by a signal level at defined bit quanta of a bit, the defined bit quanta being less than every bit quanta of a bit, and the communication device samples bit quanta other than the defined bit quanta. The module receives signal disturbances and decodes the signal disturbances as having a value different from an expected value of the certain bit. In another form, the module uses a first counter based on a clock local to the communication device and a second counter having a higher sampling rate than the first counter. Here, the module receives over the control network a synchronizing portion of a message and counts clock ticks of the second counter over a portion of the message to determine a clock rate for a module that transmitted the message.

Disclosed herein include a system and a method of synchronizing a slave device to a signal from a master device based on pulse width analysis. The pulse width analysis is a process to sample the signal at a sampling frequency of the slave device, determine varying pulse widths of the sampled signal, and determine frequency of an embedded master clock signal of the signal based on statistical analysis of the varying pulse widths. Advantageously, performing pulse width analysis allows synchronization of a slave device with the embedded master clock signal in a time and cost efficient manner. In one aspect, determining a frequency of the embedded master clock signal and adjusting an internal clock of the slave device according to the determined frequency is faster and more cost efficient than iteratively adjusting the internal clock based on feedback loop based circuitries.

Systems and methods for classifying a P25 Phase 1 downlink transmission as using either C4FM modulation or CQPSK modulation are provided. Some methods can include calculating a first signal-to-noise ratio (SNR) at or near a middle of a first symbol of a received wireless signal, calculating a second SNR at or near an edge of the first symbol, calculating a difference between the second SNR and the first SNR, determining whether the difference is greater than a threshold, and classifying a modulation technique of the received wireless signal as either C4FM modulation or CQPSK modulation based on whether the difference is greater than the threshold.

A control network communication arrangement includes a second protocol embedded into a first protocol in a way that modules supporting the second protocol may be aware of and utilize the first protocol whereas modules supporting only the first protocol may not be aware of the second protocol. Operation of modules using the second protocol does not disturb operation of the modules not configured to use or understand the second protocol. By one approach, the messages sent using the second protocol will be seen as messages sent using the first protocol but not having a message necessary to understand or as needing a particular response. In another approach, modules using the second protocol can be configured to send message during transmission of first protocol messages by other modules, the second protocol messages being triggered off of expected aspects of the message sent under the first protocol.

Disclosed herein include a system and a method of synchronizing a slave device to a signal from a master device based on pulse width analysis. The pulse width analysis is a process to sample the signal at a sampling frequency of the slave device, determine varying pulse widths of the sampled signal, and determine frequency of an embedded master clock signal of the signal based on statistical analysis of the varying pulse widths. Advantageously, performing pulse width analysis allows synchronization of a slave device with the embedded master clock signal in a time and cost efficient manner. In one aspect, determining a frequency of the embedded master clock signal and adjusting an internal clock of the slave device according to the determined frequency is faster and more cost efficient than iteratively adjusting the internal clock based on feedback loop based circuitries.