Power control circuitry for a TDMA radio frequency transmitter
First Claim
1. A transmitter including power control circuitry responsive to level control signals and a transmit intermediate frequency (IF) signal from a signal source for maintaining the magnitude of a radio frequency (RF) output signal at a power level selected from a plurality of power levels by the level control signals, said transmitter comprising:
- reference means for generating an RF reference signal;
adjusting means having variable gain for adjusting the transmit IF signal substantially in proportion to the value of a gain control signal to produce an adjusted transmit IF signal;
mixing means for combining the adjusted transmit IF signal and the RF reference signal to produce an RF transmit signal;
amplifying means for amplifying the RF transmit signal to produce the RF output signal;
detecting means coupled to the RF output signal for generating a detector output signal having a value related to the magnitude of the RF output signal; and
control means coupled to the detector output signal for, at a plurality of intervals, sampling the value of the detector output signal, and adjusting the value of the gain control signal in response to the difference between the sampled value of the detector output signal and a desired value of the selected power level.
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Accused Products
Abstract
A TDMA cellular telephone (600) includes in its transmit signal path, microphone (608), vocoder (612), data format circuitry (601), quadrature modulator (602), 90 MHz local oscillator (606), transmitter with mixer (604), transmitter filter (618), and antenna (620). In its receive signal path, the TDMA cellular telephone (600) includes receiver filter (622) coupled to antenna (620), quadrature demodulator (624), and data deformat circuitry (625). The channel frequency of TDMA cellular telephone (600) is loaded into synthesizer (616) by microcomputer (614) and applied to transmitter (604) and demodulator (624). TDMA cellular telephone (600) is controlled by microcomputer (614) which includes a memory with a control and signaling computer program stored therein. Transmitter (604) includes novel power control circuitry (100) comprised of variable gain stage (104), mixer (106), bandpass filter (109), and directional coupler (112) in a forward path, and detector (116), A/D converter (118 ), digital controller (120), and D/A converter (126) in a feedback path.
98 Citations
30 Claims
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1. A transmitter including power control circuitry responsive to level control signals and a transmit intermediate frequency (IF) signal from a signal source for maintaining the magnitude of a radio frequency (RF) output signal at a power level selected from a plurality of power levels by the level control signals, said transmitter comprising:
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reference means for generating an RF reference signal; adjusting means having variable gain for adjusting the transmit IF signal substantially in proportion to the value of a gain control signal to produce an adjusted transmit IF signal; mixing means for combining the adjusted transmit IF signal and the RF reference signal to produce an RF transmit signal; amplifying means for amplifying the RF transmit signal to produce the RF output signal; detecting means coupled to the RF output signal for generating a detector output signal having a value related to the magnitude of the RF output signal; and control means coupled to the detector output signal for, at a plurality of intervals, sampling the value of the detector output signal, and adjusting the value of the gain control signal in response to the difference between the sampled value of the detector output signal and a desired value of the selected power level. - View Dependent Claims (2, 3, 4, 5)
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6. A transmitter including power control circuitry responsive to a timing signal defining a series of transmit intervals, level control signals, and a transmit intermediate frequency (IF) signal from a signal source for maintaining during the transmit intervals the average magnitude of a radio frequency (RF) output signal at a power level selected from a plurality of power levels by the level control signals, said transmitter comprising:
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reference means for generating an RF reference signal; memory means for storing the value of a gain control signal; adjusting means having variable gain for adjusting the transmit IF signal during the transmit time intervals substantially in proportion to the stored value of the gain control signal to produce an adjusted transmit IF signal, said adjusting means substantially blocking the transmit IF signal at times other than those during the transmit intervals; mixing means for combining the adjusted transmit IF signal and the RF reference signal to produce an RF transmit signal; amplifying means for amplifying the RF transmit signal to produce the RF output signal; detecting means coupled to the RF output signal for generating a detector output signal having a value related to the average magnitude of the RF output signal; and control means coupled to the detector output signal for, substantially at the end of each transmit interval, sampling the value of the detector output signal, adjusting the value of the gain control signal in response to the difference between the sampled value of the detector output signal and a desired value of the selected power level, and storing the adjusted value of the gain control signal in the memory means. - View Dependent Claims (7, 8, 9, 10)
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11. A time-division multiple-access (TDMA) cellular telephone, comprising:
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an antenna; a TDMA transmitter coupled to the antenna for generating a transmit intermediate frequency (IF) signal and transmitting a TDMA radio frequency (RF) output signal; a TDMA receiver coupled to the antenna for receiving a TDMA RF input signal; processing means coupled to the TDMA transmitter and TDMA receiver for producing a timing signal defining a series of transmit intervals for transmitting the TDMA RF output signal and generating a plurality of level control signals for selecting a power level from a plurality of power levels; and said TDMA transmitter further including power control circuitry coupled to the timing signal and the level control signals for maintaining the magnitude of the TDMA RF output signal at the selected power level, said power control circuitry further including; reference means for generating an RF reference signal; memory means for storing the value of a gain control signal; adjusting means having variable gain for adjusting the transmit IF signal during the transmit time intervals substantially in proportion to the stored value of the gain control signal to produce an adjusted transmit IF signal, said adjusting means substantially blocking the transmit IF signal at times other than those during the transmit intervals; mixing means for combining the adjusted transmit IF signal and the RF reference signal to produce a TDMA RF transmit signal; amplifying means for amplifying the TDMA RF transmit signal to produce the TDMA RF output signal; detecting means coupled to the TDMA RF output signal for generating a detector output signal having a value related to the average magnitude of the TDMA RF output signal; and control means coupled to the detector output signal for, substantially at the end of each transmit interval, sampling the value of the detector output signal, adjusting the value of the gain control signal in response to the difference between the sampled value of the detector output signal and a desired value of the selected power level, and storing the adjusted value of the gain control signal in the memory means. - View Dependent Claims (12, 13, 14, 15)
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16. A transmitter including power control circuitry responsive to a timing signal defining a series of transmit intervals, level control signals, and a transmit intermediate frequency (IF) signal from a signal source for maintaining the average magnitude of a radio frequency (RF) output signal at a power level selected from a plurality of power levels by the level control signals during the transmit intervals, said power control circuitry comprising:
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reference means for generating an RF reference signal; quadrature modulating means for modulating the transmit IF signal with I and Q signals from a signal source to produce a modulated transmit IF signal; adjusting means having variable gain for adjusting the modulated transmit IF signal during the transmit time intervals substantially in proportion to the stored value of a gain control signal to produce an adjusted transmit IF signal, said adjusting means substantially blocking the modulated transmit IF signal at times other than those during the transmit intervals; mixing means for combining the adjusted transmit IF signal and the RF reference signal to produce an RF transmit signal; amplifying means for amplifying the RF transmit signal to produce the RF output signal; detecting means coupled to the RF output signal for generating a detector output signal having a value related to the magnitude of the RF output signal; and control means coupled to the detector output signal for sampling the value of the detector output signal a plurality of times during each transmit interval, computing a desired value of the selected power level from the I and Q signals and predetermined constants, adjusting the value of the gain control signal in response to the difference between the sampled value of the detector output signal and the desired value of the selected power level, and applying the adjusted value of the gain control signal to the adjusting means. - View Dependent Claims (17, 18, 19, 20)
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21. A time-division multiple-access (TDMA) cellular telephone, comprising:
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an antenna; a TDMA transmitter coupled to the antenna for generating a transmit intermediate frequency (IF) signal and transmitting a TDMA radio frequency (RF) output signal; a TDMA receiver coupled to the antenna for receiving a TDMA RF input signal; processing means coupled to the TDMA transmitter and TDMA receiver for producing a timing signal defining a series of transmit intervals for transmitting the TDMA RF output signal and generating a plurality of level control signals for selecting a power level from a plurality of power levels; and said TDMA transmitter further including power control circuitry coupled to the timing signal and the level control signals for maintaining the magnitude of the TDMA RF output signal at the selected power level, said power control circuitry further including; reference means for generating an RF reference signal; quadrature modulating means for modulating the transmit IF signal with I and Q signals from a signal source to produce a modulated transmit IF signal; adjusting means having variable gain for adjusting the modulated transmit IF signal during the transmit time intervals substantially in proportion to the stored value of a gain control signal to produce an adjusted transmit IF signal, said adjusting means substantially blocking the modulated transmit IF signal at times other than those during the transmit intervals; mixing means for combining the adjusted transmit IF signal and the RF reference signal to produce an RF transmit signal; amplifying means for amplifying the RF transmit signal to produce the RF output signal; detecting means coupled to the RF output signal for generating a detector output signal having a value related to the magnitude of the RF output signal; and control means coupled to the detector output signal for sampling the value of the detector output signal a plurality of times during each transmit interval, computing a desired value of the selected power level from the I and Q signals and predetermined constants, adjusting the value of the gain control signal in response to the difference between the sampled value of the detector output signal and the desired value of the selected power level, and applying the adjusted value of the gain control signal to the adjusting means. - View Dependent Claims (22, 23, 24, 25)
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26. A transmitter including power control circuitry responsive to level control signals and a transmit intermediate frequency (IF) signal from a signal source for maintaining the magnitude of a radio frequency (RF) output signal at a power level selected from a plurality of power levels by the level control signals, said power control circuitry comprising:
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first detecting means coupled to the transmit IF signal for generating a first detector output signal having a value related to the magnitude of the transmit IF signal; reference means for generating an RF reference signal; adjusting means having variable gain for adjusting the transmit IF signal substantially in proportion to the value of a gain control signal to produce an adjusted transmit IF signal; mixing means for combining the adjusted transmit IF signal and the RF reference signal to produce an RF transmit signal; amplifying means for amplifying the RF transmit signal to produce the RF output signal; second detecting means coupled to the RF output signal for generating a second detector output signal having a value related to the magnitude of the RF output signal; control means coupled to the first detector output signal for, at a plurality of intervals, sampling the value of the first detector output signal, and computing a desired value of the selected power level from the sampled value of the first detector output signal and predetermined constants; and comparing means for adjusting the value of the gain control signal in response to the difference between the value of the second detector output signal and the desired value of the selected power level. - View Dependent Claims (27, 28, 29, 30)
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Specification