Clock circuit for a microprocessor
View Patent ↗A wireless communication device is described having a transmitter that generates electromagnetic interference when operating in a transmit mode. The wireless communication device comprises a clock circuit including a first clock element configured to generate a first clock output, and a second clock element configured to generate a second clock output. Also included is a controller configured to switch between the first clock output and the second clock output when the transmitter is operating in the transmit mode.
1. A method of maintaining oscillation of a crystal oscillator in a mobile device, comprising:
detecting an edge of a clock circuit signal;
enabling a digital clock circuit when the edge is detected; and
driving the crystal oscillator with the digital clock circuit;
wherein outputs of the digital clock circuit and the crystal oscillator have substantially equivalent frequencies.
2. The method of claim 1 , wherein the method reduces effects of interference from an electromagnetic field on the crystal oscillator.
3. The method of claim 2 , wherein the electromagnetic field is generated near the crystal oscillator.
4. The method of claim 3 , wherein the electromagnetic field is a transmission signal.
5. The method of claim 1 , wherein the edge detected is a falling edge.
6. A mobile communication device, comprising:
a crystal oscillator;
a sensor for detecting an edge of a clock circuit signal; and
a controller for enabling a digital clock circuit when the edge is detected;
wherein the digital clock circuit drives the crystal oscillator;
wherein outputs of the digital clock circuit and the crystal oscillator have substantially equivalent frequencies.
7. The mobile communication device of claim 6 , wherein the effects of interference from an electromagnetic field on the crystal oscillator are reduced.
8. The mobile communication device of claim 6 , wherein the electromagnetic field is generated near the crystal oscillator.
9. The mobile communication device of claim 6 , wherein the electromagnetic field is a transmission signal.
10. The mobile communication device of claim 6 , wherein the edge detected is a falling edge.