Offset-compensated loss of signal detection methods and systems
AssigneeInphi Corporation
InventorsSimon FOREY, Rajasekhar NAGULAPALLI, Parmanand MISHRA, Michael S. HARWOOD
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Abstract
The present invention is directed to data communication. According to a specific embodiment, the present invention provides technique for loss of signal detection. A loss-of-signal detection (LOSD) device determines an analog signal indicating signal strength by subtracting a threshold offset voltage from an incoming signal. The analog signal is then processed by a switch network of an output stage circuit, which provides a digital output of loss of signal indication at a low frequency (relative to the incoming signal frequency). There are other embodiments as well.
Claims20
A loss-of-signal detection device comprising:
- a first terminal configured to receive a first input signal, the first input signal being characterized by a first frequency;
- a first hysteresis voltage source configured to apply a first predetermined hysteresis voltage to the first input signal to provide a first adjusted signal;
- a bias voltage source being configured to provide a bias voltage;
- a first transistor comprising a first gate and a first source, the first adjusted signal being coupled to the first gate;
- a second transistor comprising a second gate, a second source, and a first drain, the second gate being coupled to the bias voltage, the second source being coupled to the first source;
- and
- an output module comprising a switch network and a latch, the switch network being configured to generate an intermediate signal using a strength indicator signal received from the first drain of the second transistor and an offset associated at least with the first transistor, the latch being configured to generate a loss-of-signal indicator based on the intermediate signal at a second frequency, the second frequency being lower than the first frequency;
- wherein the switch network operates in a first phase and a second phase, the switching network being configured to determine a common offset voltage during the first phase, the switching network being configure to generate the intermediate signal during the second phase.
A communication system comprising:
- a communication link;
- a receiver comprises:
- a first input terminal comprising a first inductor and being configured to receive a first input signal from the communication link;
- an equalizer module being configured to process the first input signal;
- a core module comprising a first transistor and being coupled to the first input terminal, the core module being configured to generate an input strength signal using at least the first input signal, the first transistor being coupled to the first input terminal;
- and
- an output module comprising a latch, the output module being configured to generate a loss-of-signal indicator using at least the input strength signal and an offset associated with the first transistor and the second transistor.
A method for loss-of-signal detection (LOSD), the method comprising:
- receiving an incoming signal;
- generating a threshold voltage using a DAC;
- generating an intermediate signal by subtracting the threshold voltage;
- storing a first voltage determined using the intermediate signal by a first capacitor during a first phase;
- storing second voltage based at least on a common mode offset by a second capacitor during a second phase;
- and
- generating a loss-of-signal indication signal based the first voltage and the second voltage at a first frequency.
Dependencies are inferred from the claim text.