Transmitter having a phase control loop whose frequency bandwidth is varied in accordance with modulation modes

• US 7,085,544 B2
• Filed: 02/26/2003
• Issued: 08/01/2006
• Est. Priority Date: 05/31/2002
• 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: Kimura, Yasuyuki, Wurm, Patrick, Hikasa, Kazuhiko, Takano, Ryoichi, Freeborough, David, Henshaw, Robert Astle, Hagisawa, Hiroshi
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): CHOW, CHARLES CHIANG
• Application Number:
  US10/373,031
• Publication Number:
  US 20030224740A1
• Time in Patent Office: 1,252 Days
• Field of Search: 455/102, 455/126, 455/127.2, 455/123, 455/108, 455/522, 455/522.1, 455/110, 455/424, 455/425, 455/561, 455/136, 455/550.1, 455/575.1, 455/456.5, 455/456.6, 455/23, 455/138, 455/67.11, 455/67.16, 455/69, 455/147, 455/180.1, 455/139, 455/188.1, 455/304, 455/114.3, 455/127.4, 455/91, 455/553.1, 375/302, 375/303, 375/305, 375/271, 375/274, 375/298, 375/306, 375/307, 375/376, 375/296, 375/297, 375/285, 375/295, 375/265, 375/283, 375/345, 375/219, 331/17, 331/1.R, 331/1.A, 331/25, 331/10, 330/129, 330/282, 330/86, 330/141, 330/281, 330/149, 330/136, 330/151, 370/205, 370/347, 370/344
• US Class Current: 455/102
• CPC Class Codes: H03C 5/00 Amplitude modulation and angle modulation produced simultaneously or at will by the same modulating signal H03C7/00 takes precedence
• CPC Class Codes: H03F 1/34 Negative-feedback-circuit arrangements with or without positive feedback H03F1/02 - H03F1/30, H03F1/38 - H03F1/50, H03F3/50 take precedence ; for rejection of common mode signals H03F3/45479
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 2001/0433 with linearisation using feedback
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• 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 27/2071 in which the data are represented by the carrier phase, e.g. systems with differential coding
• 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

A transmitter adopting a polar loop system including a phase control loop for controlling the phase of a carrier signal outputted from a transmitting oscillator and an amplitude control loop for controlling the amplitude of a transmitting output signal outputted from a power amplification circuit, and designed to be capable of performing transmission using a GMSK modulation mode and transmission using an 8-PSK modulation mode. In the transmitter, the phase control loop is shared as a phase control loop for use in the GMSK modulation mode and a phase control loop for use in the 8-PSK modulation mode. A component similar to any one of components constituting a loop filter is provided in parallel therewith so that the component can be connected or disconnected in accordance with the modulation mode, for example, by use of a switching element.

Claims

1. A transmitter comprising:

a phase control loop for controlling a phase of a carrier signal outputted from a transmitting oscillator; and

an amplitude control loop for controlling an amplitude of a transmitting output signal outputted from a power amplification circuit which receives and amplifies said carrier signal,

wherein said transmitter has a first modulation mode for phase modulation only, using said phase control loop; and

a second modulation mode for both phase and amplitude modulation using both of said phase control loop and said amplitude control loop, so that said phase control loop is shared by said first modulation mode and said second modulation mode.

2. A transmitter according to claim 1, wherein a frequency bandwidth of said phase control loop for use in said second modulation mode is identical to a frequency bandwidth of said amplitude control loop for use in said second modulation mode.

3. A transmitter according to claim 1,

wherein a frequency bandwidth of said phase control loop for use in said first modulation mode is set to be narrower than a frequency bandwidth of said phase control loop for use in said second modulation mode and a frequency bandwidth of said amplitude control loop.

4. A transmitter according to claim 1, wherein:

said phase control loop includes a carrier signal detection means for detecting said carrier signal outputted from said transmitting oscillator,

a phase detection circuit for detecting a phase difference between an output of said carrier signal detection means and a signal modulated by a modulator, and

a loop filter for generating a voltage in accordance with said phase difference detected by said phase detection circuit, so that oscillation of said transmitting oscillator is controlled by said voltage generated by said loop filter,

wherein said frequency bandwidth of said phase control loop is set by components of said loop filter.

5. A transmitter according to claim 1,

wherein said phase detection circuit includes a digital phase detection circuit and an analog phase detection circuit, and

wherein said phase control loop is pulled in by said digital phase detection circuit first at a start of transmission, and then a phase of said phase control loop is locked by said analog phase detection circuit before or after a start of power amplification.

6. A transmitter according to claim 5,

wherein a phase shifter for shifting by 90 degrees either a phase of a feedback signal or a phase of a signal from a modulator is provided in a stage before either of said digital phase detection circuit and said analog phase detection circuit.

7. A transmitter according to claim 1,

wherein said amplitude control loop includes:

output power detection means for detecting said transmitting output signal outputted from said power amplification circuit;

an amplitude detection circuit for detecting an amplitude difference between a feedback signal detected by said output power detection means and said signal modulated by a modulator;

a second loop filter for holding a voltage proportional to said amplitude difference detected by said amplitude detection circuit;

a first variable gain amplification circuit provided on a feedback path between said output power detection means and said amplitude detection circuit and for amplifying said signal detected by said output power detection means; and

a second variable gain amplification circuit provided on a forward path between said second loop filter and said power amplification circuit; and

wherein;

a gain of said first variable gain amplification circuit is set in accordance with an output control voltage in said second modulation mode while a gain of said second variable gain amplification circuit is controlled inversely to that of said first variable gain amplification circuit.

8. A transmitter according to claim 7,

wherein said second loop filter includes a first filter for providing a frequency bandwidth required in said second modulation mode, a second filter for providing a frequency bandwidth narrower than said frequency bandwidth determined by said first filter, and switching means for selecting either said first filter or said second filter,

wherein said second loop filter provides a frequency bandwidth for said amplitude control loop, and

wherein said power amplification circuit is arranged to be controlled in accordance with said output control voltage in said first modulation mode by said amplitude control loop which has said second filter connected as said second loop filter.

9. A transmitter according to claim 7,

wherein said phase control loop includes a carrier signal detection means for detecting said carrier signal outputted from said transmitting oscillator;

and

wherein said transmitter further comprises;

switching means for selecting either said signal detected by said carrier signal detection means or said signal detected by said output power detection means, as a feedback signal to said phase detection circuit.

10. A transmitter according to claim 1, further comprising switching means for switching components of a loop filter determining a frequency bandwidth of said phase control loop in accordance with said modulation modes.

11. A transmitter comprising:

a semiconductor integrated circuit having a base band circuit for generating I and Q signals in accordance with transmitting data;

a transmitting oscillator for generating a carrier signal;

a power amplification circuit for amplifying said carrier signal outputted from said transmitting oscillator;

transmitting output power level detection means for detecting a level of a signal outputted from said power amplification circuit; and

a semiconductor integrated circuit for modulation including

an orthogonal modulator for modulating said I and Q signals onto said carrier signal so as to form an oscillating signal of a predetermined frequency,

a phase control loop for controlling a phase of said carrier signal outputted from said transmitting oscillator,

an amplitude control loop for controlling an amplitude of a transmitting output signal outputted from said power amplification circuit,

a first variable gain amplification circuit provided on a feedback path between said transmitting output power level detection means and an amplitude detection circuit, and

a second variable gain amplification circuit provided on a forward path between said amplitude detection circuit and said power amplification circuit;

wherein said transmitter has a first modulation mode and a second modulation mode, and

wherein said phase control loop is shared by said first modulation mode and said second modulation mode.

12. A transmitter for generating a modulated carrier signal, comprising:

a first operating mode which modulates a phase component and an amplitude component of a carrier signal, and a second operating mode which modulates a phase component, but not an amplitude component, of said carrier signal;

a first control loop for controlling amplitude and a second control loop for controlling phase in said first operating mode;

wherein said first control loop is used for the acquisition of a phase lock in said first operating mode at the start-up time of output of said transmitter, and

wherein said second control loop is used to control the phase of the modulated carrier signal in said second operating mode, and in said first operating mode before the start-up time of output of said transmitter.

13. A transmitter for emitting a modulated carrier signal,

said transmitter having a first operating mode in which the phase and the amplitude of the carrier signal are modulated, a second operating mode in which only the phase of the carrier signal is modulated, and a control loop for controlling the modulation of the carrier signal,

wherein said control loop comprises processing means for controlling the phase of the carrier signal, and said processing means is used for phase modulation control in both of said first operating mode and said second operating mode.