Low power wake on radio

An apparatus comprising:

• an analog portion of a wake on radio circuit configured to supply a plurality of detection indications sequentially from a comparator, each of the detection indications having a first value to indicate that a radio frequency (RF) signal was detected on an input of the wake on radio circuit and having a second value to indicate that no RF signal was detected on the input;
• a digital portion of the wake on radio circuit coupled to the comparator, wherein the digital portion is configured to incrementally turn on decode logic to decode whether a radio transmission intended for the wake on radio circuit has been received based on a plurality of the detection indications supplied by the comparator;
• wherein the digital portion includes,
• first high symbol detect logic coupled to the comparator to determine whether a first high symbol was received based on one of the detection indications;
• first preamble bit detect logic that is off while the first high symbol is being detected, wherein the digital portion is responsive to detecting the first high symbol to turn on the first preamble bit detect logic to detect a first bit of a preamble that includes the first high symbol;
• and
• preamble detect logic to detect the preamble, the preamble detect logic being off while the first bit of the preamble is being detected by the first preamble bit detect logic, and the preamble detect logic is turned on to detect the preamble responsive to detection of the first bit of the preamble.

An apparatus comprising:

• an analog portion of a wake on radio circuit to detect a radio frequency (RF) signal present on an input to the wake on radio circuit and to indicate on a signal line presence of the RF signal and absence of the RF signal;
• a digital portion of the wake on radio circuit coupled to the signal line, the digital portion including,
• first high symbol detect logic coupled to the signal line to detect a first high symbol;
• first preamble bit detect logic, wherein the first preamble bit detect logic is off while the first high symbol is being detected and responsive to detection of the first high symbol, the first preamble bit detect logic is enabled and used to detect a first bit of a preamble that includes the first high symbol;
• preamble detect logic to detect the preamble, wherein the preamble detect logic is off while the first bit of the preamble is being detected and the preamble detect logic is enabled responsive to detection of the first bit of the preamble;
• identification sequence detection logic to detect an identification sequence unique to the wake on radio circuit, the identification sequence detection logic being enabled responsive to detection of the preamble;
• and
• wherein responsive to detecting the identification sequence, the digital portion generates a wakeup signal to wake up circuitry kept in a low power state until the identification sequence unique to the wake on radio circuit, is detected.