Bidirectional data transmission over isolation medium

An apparatus comprising:

• a first controller having first differential modulation control outputs and including a programmable delay circuit, the first controller configurable to provide first differential modulation signals having a particular frequency at the first differential modulation control outputs;
• a first differential modulator circuit coupled between first differential terminals and second differential terminals, the first differential modulator circuit having first differential modulation control inputs coupled to the first differential modulation control outputs, and the first differential modulator circuit configurable to:
• modulate first differential signals at the first differential terminals with the first differential modulation signals having the particular frequency;
• provide the modulated first differential signals at the second differential terminals;
• modulate modulated second differential signals at the second differential terminals with the first differential modulation signals having the particular frequency to recover second differential signals;
• and
• provide the recovered second differential signals at the first differential terminals;
• a second controller having second differential modulation control outputs and configurable to provide second differential modulation signals having the particular frequency at the second differential modulation control outputs;
• a second differential modulator circuit coupled between third differential terminals and fourth differential terminals, the second differential modulator circuit having second differential modulation control inputs coupled to the second differential modulation control outputs, and the second differential modulator circuit configurable to:
• modulate the modulated first differential signals at the third differential terminals with the second differential modulation signals having the particular frequency to recover the first differential signals;
• provide the recovered first differential signals at the fourth differential terminals;
• modulate second differential signals at the fourth differential terminals with the second differential modulation signals having the particular frequency;
• and
• provide the modulated second differential signals at the third differential terminals.

An apparatus comprising:

• a controller having a modulation control output and including a programmable delay circuit, the controller configurable to provide a modulation signal having a particular frequency at the modulation control output;
• and
• a modulator circuit coupled between a first terminal and a second terminal, the modulator circuit having a modulation control input coupled to the modulation control output, and the modulator circuit configurable to:
• modulate a first signal at the first terminal with the modulation signal having the particular frequency;
• provide the modulated first signal at the second terminal;
• modulate a second signal at the second terminal with the modulation signal having the particular frequency;
• and
• provide the modulated second signal at the first terminal.