Universal transmitter
First Claim
1. A universal transmitter, comprising:
- an input circuit including an antenna, a central processing unit (CPU) coupled to the input circuit, and a radio frequency (RF) circuit coupled to the CPU;
said CPU to generate a plurality of discrete digital outputs;
said RF circuit, in response to the plurality of digital outputs, to generate and transmit a local RF signal at a corresponding plurality of discrete scanning frequencies;
said input circuit to receive the local RF signal and a template RF signal including a target frequency and a modulation pattern, and to mix the local RF signal and the template RF signal and provide a mixed signal; and
said CPU to sample the mixed signal at the plurality of scanning frequencies, and to determine the target frequency of the template RF signal in response to the plurality of samples.
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Abstract
A method and apparatus for a universal transmitter that can learn and emulate the transmission frequency and modulation pattern of a template transmitter, without prior knowledge of such information. The universal transmitter is then operable to transmit the “learned” modulation pattern and transmission frequency to actuate a remote control receiver operable with the template transmitter. The universal transmitter is capable of recognizing a fixed- code pulse-modulated, frequency shift keying, or other transmission without prior knowledge of the frequency and modulation pattern. The universal transmitter includes multiple programmable switches to allow the universal transmitter to learn the modulation pattern and frequency of multiple transmitting sources and store the values in non-volatile memory.
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Citations
23 Claims
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1. A universal transmitter, comprising:
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an input circuit including an antenna, a central processing unit (CPU) coupled to the input circuit, and a radio frequency (RF) circuit coupled to the CPU;
said CPU to generate a plurality of discrete digital outputs;
said RF circuit, in response to the plurality of digital outputs, to generate and transmit a local RF signal at a corresponding plurality of discrete scanning frequencies;
said input circuit to receive the local RF signal and a template RF signal including a target frequency and a modulation pattern, and to mix the local RF signal and the template RF signal and provide a mixed signal; and
said CPU to sample the mixed signal at the plurality of scanning frequencies, and to determine the target frequency of the template RF signal in response to the plurality of samples. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 16, 17, 18, 19, 20, 21, 23)
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2. The transmitter of claim 2 wherein the CPU to (i) incrementally increase the scanning frequency of the local RF signal by a first predetermined amount, starting from a lower scanning frequency, until a magnitude of the mixed signal, above a lower threshold value, is detected, (ii) incrementally increase the scanning frequency of the local RF signal by a second predetermined amount until the magnitude of the mixed signal falls to or below the lower threshold value, (iii) store the current scanning frequency as a first frequency;
- (iv) increase the scanning frequency by a third predetermined amount;
(v) incrementally decrease the scanning frequency by a fourth predetermined increments until the magnitude of the mixed signal falls to or below the lower threshold value;
(vi) store the current scanning frequency as a second frequency, and (vii) determine the target frequency as being between the first and second frequencies.
- (iv) increase the scanning frequency by a third predetermined amount;
- 3. The transmitter of claim 3 wherein the CPU to set the scanning frequency of the local RF signal to a frequency below the first frequency or above the second frequency, and to sample the mixed signal at the set scanning frequency to determine the modulation pattern of the template RF signal.
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15. A method of learning a target frequency and modulation pattern of a template transmitter, comprising:
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transmitting, by an radio frequency (RF) circuit, a local RF signal at a lower scanning frequency;
concurrently receiving and mixing, by an input circuit, the local RF signal and a template RF signal including a target frequency and a modulation pattern, to provide an output signal;
incrementally increasing the scanning frequency of the local RF signal, by a first predetermined amount, until a magnitude of the output signal that is above a first threshold value is detected;
incrementally increasing the scanning frequency of the local RF signal, by a second predetermined amount, until the magnitude of the output signal falls to or below a second threshold value;
storing the current scanning frequency as a first frequency;
increase the scanning frequency of the local RF signal by a third predetermined amount;
incrementally decreasing the scanning frequency of the local RF signal, by a fourth predetermined amount, until the magnitude of the output signal falls to or below a third threshold value;
storing the current scanning frequency as a second frequency;
determining the target frequency as a function of the first and second frequencies;
adjusting the scanning frequency of the local RF signal to below the first frequency or greater than the second frequency; and
sampling the output signal a plurality of times to determine the modulation pattern of the template RF signal.
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22. A computer program product, comprising:
a computer usable medium having computer readable program code embodied therein to learn the target frequency and modulation pattern of a template transmitter in a universal transmitter, the computer readable program code in said computer program product comprising;
first computer readable program code to generate a set of discrete digital outputs to cause a radio frequency (RF) circuit to generate and transmit a local RF signal at a corresponding set of discrete scanning frequencies;
second computer readable program code to sample an input signal at the set of scanning frequencies, said input signal being a function of the local RF signal and a template RF signal including a target frequency and modulation pattern; and
third computer readable program code to determine the target frequency of the template RF signal in response to the plurality of samples.
Specification