System and method for determining a distance between networked electronic devices each comprising a loudspeaker and a microphone

A system for determining a distance between a first networked electronic device and a second networked electronic device, the system comprising:

• the first networked electronic device having a first loudspeaker and a first microphone;
• and
• the second networked electronic device having a second loudspeaker and a second microphone,
• wherein the first networked electronic device further comprises first circuitry configured to:
• define a first sound signal comprising a first measuring wave having a first frequency carried on a first carrier wave having a first carrier frequency being higher than the first frequency, wherein the first sound signal is sinusoidal amplitude modulated, and
• drive the first loudspeaker to emit the first sound signal;
• wherein the second networked electronic device further comprises second circuitry configured to:
• analyze the first sound signal upon its registration by the second microphone,
• define a second sound signal comprising a second measuring wave having the first frequency carried on a second carrier wave having a second carrier frequency being higher than the first frequency and different from the first carrier frequency, wherein the second sound signal is sinusoidal amplitude modulated and wherein defining the second sound signal comprises setting the phase of the second measuring wave to be the same as a phase of the first measuring wave of the first sound signal received by the second microphone thereby a phase of the second measuring wave is set such that it simulates a reflection of the first measuring wave of the first sound signal on the second networked electronic device, and
• drive the second loudspeaker to emit the second sound signal;
• wherein the first circuitry of the first networked electronic device is further configured to:
• analyze the second sound signal upon its registration by the first microphone,
• determine a phase shift between the emitted first measuring wave and the received second measuring wave, and
• calculate the distance between the first networked electronic device and the second networked electronic device based on the determined phase shift.