Single crystal oscillator RF transmitter system

• US 20040152427A1
• Filed: 01/22/2004
• Published: 08/05/2004
• Est. Priority Date: 01/30/2003
• Status: Abandoned Application

• Current Assignee: Elan Microelectronics Corporation
• Original Assignee: Elan Microelectronics Corporation
• Inventors: Sun, Ben-Chang, Lin, Ki-Dar, Tang, Chong-Hao, Chiu, Yen-Chang
• Application Number:
  US10/761,340
• Publication Number:
  US 20040152427A1
• Time in Patent Office: Days
• US Class Current: 455/85
• CPC Class Codes: H04B 1/04 Circuits

Abstract

A single crystal oscillator RF transmitter system converts a data to be transmitted into RF packets by a converter under the control of a microprocessor, receives the RF packets and generates an RF signal accordingly to be sent out by a transmitter. The system comprises a local oscillator to generate a first clock in response to an external crystal to provide for the transmitter and connected to a clock switch which divides the frequency of the first clock so as to generate a second clock to the microprocessor and a third clock to the converter. Alternatively, an RC oscillator generates a fourth clock for the clock switch to provide the second and third clocks for the microprocessor and converter, respectively.

Claims

1. A single crystal oscillator RF transmitter system comprising:

a microprocessor;

a converter for converting a data to be transmitted into RF packets;

a local oscillator responsive to an external crystal for generating a first clock;

a clock switch, connected with the first clock, for providing a second clock to the microprocessor and a third clock to the converter; and

a transmitter connected with the first clock and RF packets for generating an RF signal to be sent out.

2. The system of claim 1, wherein the clock switch comprises a frequency divider for frequency-dividing the first clock to generate the second clock.

3. The system of claim 1, wherein the clock switch comprises a frequency divider for frequency-dividing the first clock to generate the third clock.

4. The system of claim 1, further comprising an RC oscillator for generating the second clock.

5. The system of claim 4, wherein the clock switch comprises a frequency divider for frequency-dividing the first clock to generate the third clock.

6. The system of claim 4, wherein the RC oscillator is connected with an external resistor for tuning the second clock.

7. The system of claim 6, wherein the external resistor comprises a variable resistor.

8. The system of claim 4, wherein the RC oscillator comprises a resistor network for determining the second clock.

9. The system of claim 4, wherein the microprocessor signals the local oscillator to turn off after the RF signal is sent out.

10. The system of claim 4, wherein the converter and transmitter signal the local oscillator to turn off after the RF signal is sent out.

11. The system of claim 1, further comprising a peripheral circuit connected to the microprocessor.

12. The system of claim 1, wherein the microprocessor, converter, local oscillator, clock switch and transmitter are integrated on a chip.

13. The system of claim 4, wherein the microprocessor, converter, local oscillator, clock switch, RC oscillator and transmitter are integrated on a chip.

14. A method for transmitting a data by sending out an RF signal by a single crystal oscillator RF transmitter system including a microprocessor connected with a converter that is further connected to a transmitter, the method comprising the steps of:

generating a first clock responsive to the single crystal oscillator for providing to the transmitter;

generating a second clock and a third clock from the first clock for providing to the microprocessor and converter, respectively;

converting the data into RF packets by the converter for providing to the transmitter; and

generating the RF signal from the RF packets and sending out the RF signal by the transmitter.

15. The method of claim 14, wherein the step of generating a second clock and a third clock from the first clock comprises the step of frequency-dividing the first clock.

16. A method for transmitting a data by sending out an RF signal by a single crystal oscillator RF transmitter system including a microprocessor connected with a converter that is further connected to a transmitter, the method comprising the steps of:

generating a first clock by an RC oscillator;

generating a second clock from the first clock for providing to the microprocessor;

generating a third clock responsive to the single crystal oscillator;

generating a fourth clock from the third clock for providing to the converter;

converting the data into RF packets by the converter; and

receiving the RF packets and the first clock by the transmitter at which to generate the RF signal send out.

17. The method of claim 16, wherein the step of generating a fourth clock from the third clock comprises the step of frequency-dividing the third clock.

18. The method of claim 16, further comprising the step of tuning an external resistor connected to the RC oscillator for determining the first clock.

19. The method of claim 16, further comprising the step of trimming a built-in resistor network connected to the RC oscillator for determining the first clock.

20. The method of claim 16, further comprising the step of signaling the single crystal oscillator to stop generating the third clock after sending out the RF signal.

21. The method of claim 16, further comprising the step of signaling the converter to turn off after sending out the RF signal.

22. The method of claim 16, further comprising the step of signaling the transmitter to turn off after sending out the RF signal.