US 11,809,772 B1
Systems and methods for detection status of intercom termination
Victor Lerner, Carlsbad, CA (US); and Charles Butten, Richmond, CA (US)
Assigned to H.M. Electronics, Inc., Carlsbad, CA (US)
Filed by H.M. Electronics, Inc., Carlsbad, CA (US)
Filed on Jun. 28, 2023, as Appl. No. 18/343,527.
Int. Cl. G06F 3/16 (2006.01)
CPC G06F 3/162 (2013.01) 20 Claims
OG exemplary drawing
 
1. A system configured to detect termination status in an audio communication system having a first audio channel, wherein termination status indicates whether exactly one termination circuit is part of the first audio channel of the audio communication system, the system comprising:
a Current Source (CS) that includes and drives a resistive load (RL) having a first connection and a second connection, wherein the Current Source has an input configured to accept an input voltage, wherein the Current Source is configured to create a voltage differential between the first and second connections of the resistive load, wherein the second connection of the resistive load is connected to the first audio channel of the audio communication system, wherein the Current Source has an output connected to the first connection of the resistive load, and wherein the Current Source is a voltage-controlled Current Source;
an alternating current (AC) voltage generator configured to generate an AC voltage, wherein the AC voltage is used to create the input voltage for the Current Source;
a first set of one or more filters having a first input, wherein the first input is connected to the output of the Current Source, and wherein the first set of one or more filters is configured to generate a first analog output signal;
a second set of one or more filters having a second input, wherein the second input is connected to the second connection of the resistive load, and wherein the second set of one or more filters is configured to generate a second analog output signal;
first circuitry configured to determine a ratio of (i) a first magnitude of the first analog output signal and (ii) a second magnitude of the second analog output signal; and
second circuitry configured to determine the termination status by a comparison using the ratio.