Method of ramping up output level of power amplifier of radio communication system, communication semiconductor integrated circuit, and radio communication system

• US 7,324,787 B2
• Filed: 07/29/2004
• Issued: 01/29/2008
• Est. Priority Date: 07/31/2003
• Status: Expired due to Fees

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.), TTPCom Ltd. (Motorola Solutions, Inc.)
• Original Assignee: TTPCom Ltd. (Motorola Solutions, Inc.), Renesas Technology Corporation (Renesas Electronics Corporation)
• Inventors: Wurm, Patrick, Hikasa, Kazuhiko, Takano, Ryoichi, Kurakami, Noriyuki
• Primary Examiner(s): Le; Lana
• Assistant Examiner(s): DAGLAWI, AMAR A
• Application Number:
  US10/901,195
• Publication Number:
  US 20050064828A1
• Time in Patent Office: 1,279 Days
• Field of Search: 455/115.1, 455/127.1, 455/69, 455/194.2, 455/311, 455/522, 455/127.2, 455/88, 455/13.4, 375/300, 375/302
• US Class Current: 455/69
• CPC Class Codes: H03G 3/3047 for intermittent signals, e.g. burst signals
• CPC Class Codes: H04L 27/2017 in which the phase changes are non-linear, e.g. generalized and Gaussian minimum shift keying, tamed frequency modulation H04L27/201 takes precedence
• CPC Class Codes: H04L 27/361 Modulation using a single or unspecified number of carriers, e.g. with separate stages of phase and amplitude modulation

Abstract

In a radio communication system having a phase control loop for phase modulation and an amplitude control loop for amplitude modulation and being capable of time divisional transmission and reception under a predetermined time management, when transmission in a first mode is switched to transmission in a second mode or when transmission in the second mode is switched to transmission in the first mode, the output level of the power amplifier is lowered once to a predetermined level higher than the level when transmission related circuits are activated, and thereafter the output level of the power amplifier is again ramped after the settings have been changed but without starting of a transmission oscillator, establishing of the phase control loop and the amplitude control loop.

Claims

1. A method of ramping up an output level of a power amplifier of a radio communication system having a transmission oscillator, a phase detection circuit for comparing a phase of a reference signal with a phase of a feedback signal to control the transmission oscillator in accordance with a detected phase difference, said power amplifier which amplifies an oscillation signal generated by the transmission oscillator, and an amplitude detection circuit for comparing an amplitude of a reference signal with an amplitude of a feedback signal to control the power amplifier in accordance with a detected amplitude difference, wherein the radio communication system transmits, by phase modulation, a transmission signal by using a phase control loop including the phase detection circuit, and transmits, by phase and amplitude modulation, a transmission signal by using the phase control loop and an amplitude control loop including the amplitude detection circuit, said method of ramping up an output level of a power amplifier comprising steps of:

performing activation of the transmission oscillator, establishment of the phase control loop including the phase detection circuit, establishment of the amplitude control loop including the amplitude detection circuit, and ramp-up of the output level of the power amplifier, in this order recited, for activation of transmission related circuits; and

lowering the output level of the power amplifier to a predetermined level higher than a level when the transmission related circuits are activated, while the transmission oscillator is maintained to operate, and thereafter ramping again the output level of the power amplifier without activation of the transmission oscillator, establishment of the phase control loop and establishment of the amplitude control loop, when transmission by phase modulation is switched to transmission by phase and amplitude modulation or when transmission by phase and amplitude modulation is switched to transmission by phase modulation,

wherein after establishment of the phase control loop and before establishment of the amplitude control loop including the amplitude detection circuit, by using precharging means provided on a forward path in the amplitude control loop from the amplitude detection circuit to the power amplifier, the forward path is precharged up to a predetermined level faster than when an output of the amplitude detection circuit is used.

2. A method of ramping up an output of a power amplifier according to claim 1, wherein transmission by the phase modulation has a first mode in which the output level of the power amplifier is indirectly controlled by using the amplitude control loop and a second mode in which the output level of the power amplifier is directly controlled without using the amplitude control loop;

and

when transmission in the first mode is switched to transmission in the second mode or when transmission in the second mode is switched to transmission in the first mode, the output level of the power amplifier is lowered to the predetermined level higher than the level when the transmission related circuits are activated, while the transmission oscillator is maintained to operate, and thereafter ramping again the output level of the power amplifier without operating the precharge means.

3. A method of ramping up an output level of a power amplifier of a radio communication system having a transmission oscillator, a phase detection circuit for comparing a phase of a reference signal with a phase of a feedback signal to control the transmission oscillator in accordance with a detected phase difference, said power amplifier which amplifies an oscillation signal generated by the transmission oscillator, and an amplitude detection circuit for comparing an amplitude of a reference signal with an amplitude of a feedback signal to control the power amplifier in accordance with a detected amplitude difference, wherein the radio communication system transmits, by phase modulation, a transmission signal by using a phase control loop including the phase detection circuit, and transmits, by phase and amplitude modulation, a transmission signal by using the phase control loop and an amplitude control loop including the amplitude detection circuit, said method of ramping up an output level of a power amplifier comprising steps of:

performing activation of the transmission oscillator, establishment of the phase control loop including the phase detection circuit, establishment of the amplitude control loop including the amplitude detection circuit, and ramp-up of the output level of the power amplifier, in this order recited, for activation of transmission related circuits; and

lowering the output level of the power amplifier to a predetermined level higher than a level when the transmission related circuits are activated, while the transmission oscillator is maintained to operate, and thereafter ramping again the output level of the power amplifier without activation of the transmission oscillator, establishment of the phase control loop and establishment of the amplitude control loop, when transmission by phase modulation is switched to transmission by phase and amplitude modulation or when transmission by phase and amplitude modulation is switched to transmission by phase modulation,

wherein the phase control loop includes a first phase control loop for supplying a feedback signal from an output side of the transmission oscillator to the phase detection circuit, and a second phase control loop for supplying a feedback signal from an output side of the power amplifier to the phase detection circuit, and establishment of the phase control loon is performed first for the first phase control loop and next for the second phase control loop, and

wherein when transmission only by the phase modulation is activated, after establishment of the phase control loop and before establishment of the amplitude control loop including the amplitude detection circuit, by using precharge means provided on a forward path in the amplitude control loop from the amplitude detection circuit to the power amplifier, the forward path is precharged up to a predetermined level faster than when an output of the amplitude detection circuit is used, and after precharge by the precharge means, the phase control loop is switched from the first phase control loop to the second phase control loop.

4. A method of ramping up an output level of a power amplifier of a radio communication system having a transmission oscillator, a phase detection circuit for comparing a phase of a reference signal with a phase of a feedback signal to control the transmission oscillator in accordance with a detected phase difference, said power amplifier which amplifies an oscillation signal generated by the transmission oscillator, and an amplitude detection circuit for comparing an amplitude of a reference signal with an amplitude of a feedback signal to control the power amplifier in accordance with a detected amplitude difference, wherein the radio communication system transmits, by phase modulation, a transmission signal by using a phase control loop including the phase detection circuit, and transmits, by phase and amplitude modulation, a transmission signal by using the phase control loop and an amplitude control loop including the amplitude detection circuit, said method of ramping up an output level of a power amplifier comprising steps of:

performing activation of the transmission oscillator, establishment of the phase control loop including the phase detection circuit, establishment of the amplitude control loop including the amplitude detection circuit, and ramp-up of the output level of the power amplifier, in this order recited, for activation of transmission related circuits; and

lowering the output level of the power amplifier to a predetermined level higher than a level when the transmission related circuits are activated, while the transmission oscillator is maintained to operate, and thereafter ramping again the output level of the power amplifier without activation of the transmission oscillator, establishment of the phase control loop and establishment of the amplitude control loop, when transmission by phase modulation is switched to transmission by phase and amplitude modulation or when transmission by phase and amplitude modulation is switched to transmission by phase modulation,

wherein the phase detection circuit includes a digital phase detection circuit and an analog phase detection circuit, and establishment of the phase control loop is performed first by using the digital phase detection circuit and next by using the analog phase detection circuit, and

wherein when transmission only by the phase modulation is activated, after establishment of the phase control loop and before establishment of the amplitude control loop including the amplitude detection circuit, by using precharge means provided on a forward path in the amplitude control loop from the amplitude detection circuit to the power amplifier, the forward path is precharged up to a predetermined level faster than when an output of the amplitude detection circuit is used, and after precharge of the forward path by the precharge means, the digital phase detection circuit is switched to the analog phase detection circuit.

5. A method of ramping up an output level of a power amplifier of a radio communication system having a transmission oscillator, a phase detection circuit for comparing a phase of a reference signal with a chase of a feedback signal to control the transmission oscillator in accordance with a detected phase difference, said power amplifier which amplifies an oscillation signal generated by the transmission oscillator, and an amplitude detection circuit for comparing an amplitude of a reference signal with an amplitude of a feedback signal to control the power amplifier in accordance with a detected amplitude difference, wherein the radio communication system transmits, by phase modulation, a transmission signal by using a phase control loop including the phase detection circuit, and transmits, by phase and amplitude modulation, a transmission signal by using the phase control loop and an amplitude control loon including the amplitude detection circuit, said method of ramping up an output level of a power amplifier comprising steps of:

performing activation of the transmission oscillator, establishment of the phase control loop including the phase detection circuit, establishment of the amplitude control loop including the amplitude detection circuit, and ramp-up of the output level of the power amplifier, in this order recited, for activation of transmission related circuits; and

lowering the output level of the power amplifier to a predetermined level higher than a level when the transmission related circuits are activated, while the transmission oscillator is maintained to operate, and thereafter ramping again the output level of the power amplifier without activation of the transmission oscillator, establishment of the phase control loop and establishment of the amplitude control loop, when transmission by phase modulation is switched to transmission by phase and amplitude modulation or when transmission by phase, and amplitude modulation is switched to transmission by phase modulation,

wherein the phase detection circuit includes a digital phase detection circuit and an analog phase detection circuit and establishment of the phase control loop is performed first by using the digital phase detection circuit and next by using the analog phase detection circuit, and

wherein when transmission by the phase and amplitude modulation is activated, after establishment of the phase control loop, the digital phase detection circuit is switched to the analog phase detection circuit, and before establishment of the amplitude control loop including the amplitude detection circuit, by using precharge means provided on a forward path in the amplitude control loop from the amplitude detection circuit to the power amplifier, the forward path is precharged up to a predetermined level faster than when an output of the amplitude detection circuit is used, and after precharge by the precharge means, the forward path of the amplitude control loop is validated.