Wireless connections with virtual hysteresis
Circuit connectors for establishing EHF communication include a receiver configured to receive a transmitted EHF electromagnetic signal, and an output circuit coupled to the receiver. The output circuit has two states of operation that correspond to enabling a signal output and disabling the signal output. The output circuit is also configured to change its state of operation responsive to a state of a control signal, and a controller is coupled to the receiver and configured to produce the control signal. The control signal has two states that correspond to a first condition when the received signal exceeds a first threshold and a second condition when the received signal is less than a second threshold.
1. A first contactless connector included in a first device for communicating with a second contactless connector included in a second device using extremely high frequency (EHF) signals, the first contactless connector comprising:
a receiver configured to receive a transmitted EHF electromagnetic signal from the second contactless connector;
an output circuit coupled to the receiver configured to output the transmitted EHF electromagnetic signal when a control signal has a first state and configured to not output the transmitted EHF electromagnetic signal when the control signal has a second state; and
a hysteresis controller coupled to the receiver and the output circuit, the hysteresis controller comprising a rate circuit configured to determine a rate of change of a signal strength of the received EHF electromagnetic signal, the hysteresis controller configured to produce the control signal having the second state if the determined rate of change is greater than a specified threshold.
2. The first contactless connector of claim 1 , wherein determining the rate of change comprises determining a period of time between a time the signal strength reaches a lower threshold and a time the signal strength reaches an upper threshold, and wherein the hysteresis controller is configured to:
compare the period of time with a specified reference value; and
produce the control signal having the second state if the period of time is less than the specified reference value.
3. The first contactless connector of claim 2 , wherein the hysteresis controller is further configured to produce the control signal having the first state if the period of time is greater than or equal to the specified reference value.
4. The first contactless connector of claim 1 , wherein the hysteresis controller is further configured to:
determine the signal strength of the received EHF electromagnetic signal;
produce the control signal having the second state until the determined signal strength exceeds a first threshold for a first time interval, whereupon the controller produces the control signal having the first state to enable the output circuit to output the transmitted EHF signal from the receiver; and thereafter
produce the control signal with the second state to disable the output circuit from outputting the transmitted EHF signal from the receiver when the determined signal strength fails to meet a second threshold for a second time interval.
5. The first contactless connector of claim 4 , wherein the first and second thresholds are the same, and the first and second time intervals are the same.
6. The first contactless connector of claim 4 , wherein the first threshold is greater than the second threshold.
7. The first contactless connector of claim 4 , wherein the first signal strength threshold and the first time interval are user-selectable.
8. The first contactless connector of claim 4 , the hysteresis controller further comprising a first timer configured to receive a timer control signal and measure the first time interval.
9. The first contactless connector of claim 8 , the hysteresis controller further comprising a second timer configured to receive the timer control signal and measure the second time interval.
10. The first contactless connector of claim 4 , wherein the receiver includes an integrated circuit package having an antenna embedded in the package and configured to receive the transmitted EHF electromagnetic signal.