Frequency band select phase lock loop device
First Claim
1. A phase lock loop (PLL) device, comprising:
- a phase and frequency detector coupled to a frequency reference signal having a first frequency and to a second input frequency signal for generating an output error signal based on frequency and phase information contained in the frequency reference signal and the second input frequency signal;
a filter and compensation circuit coupled to the output error signal of the phase and frequency detector, the filter and compensation circuit including a first low-pass filter for generating a first feedback signal, and a second low-pass filter for generating a second feedback signal based on the error signal;
a controller coupled to the second feedback signal for generating a frequency adjust signal; and
a voltage controlled oscillator (VCO) coupled to the first feedback signal and to the frequency adjust signal for generating an output frequency signal to be provided to the phase and frequency detector as its second input frequency signal, the output frequency signal having a second frequency which is controlled by both the first feedback signal and the frequency adjust signal;
whereby the phase and frequency detector, the filter and compensation circuit and the voltage controlled oscillator form a phase lock loop to lock the second frequency to the first frequency.
2 Assignments
0 Petitions
Accused Products
Abstract
A multi-band phase lock loop (PLL) device for use in a communication system. The PLL comprises a frequency reference oscillator, a reference frequency divider, a phase and frequency detector, a filter and compensation circuit, a microcontroller, a multi-band voltage controlled oscillator (VCO), and a feedback divider. A fast feedback signal is provided to the VCO for phase locking operation. A slow feedback signal is used by the microcontroller to generate a frequency adjust signal for frequency band centering for the VCO. The microcontroller also controls the VCO to change the frequency band of operation. The PLL device may be used in a communication system that operate in both the cellular frequency band and the PCS frequency band.
74 Citations
24 Claims
-
1. A phase lock loop (PLL) device, comprising:
-
a phase and frequency detector coupled to a frequency reference signal having a first frequency and to a second input frequency signal for generating an output error signal based on frequency and phase information contained in the frequency reference signal and the second input frequency signal; a filter and compensation circuit coupled to the output error signal of the phase and frequency detector, the filter and compensation circuit including a first low-pass filter for generating a first feedback signal, and a second low-pass filter for generating a second feedback signal based on the error signal; a controller coupled to the second feedback signal for generating a frequency adjust signal; and a voltage controlled oscillator (VCO) coupled to the first feedback signal and to the frequency adjust signal for generating an output frequency signal to be provided to the phase and frequency detector as its second input frequency signal, the output frequency signal having a second frequency which is controlled by both the first feedback signal and the frequency adjust signal; whereby the phase and frequency detector, the filter and compensation circuit and the voltage controlled oscillator form a phase lock loop to lock the second frequency to the first frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A phase lock loop (PLL) device, comprising:
-
a phase and frequency detector coupled to a frequency reference signal having a first frequency and to a second input frequency signal for generating an output error signal based on frequency and phase information contained in the frequency reference signal and the second input frequency signal; a filter and compensation circuit coupled to the output error signal of the phase and frequency detector for generating a first and a second feedback signal based on the error signal; a controller coupled to the second feedback signal and to a band select input for generating a frequency adjust signal and a band select signal; and a voltage controlled oscillator (VCO) coupled to the first feedback signal, the band select signal, and the frequency adjust signal for generating an output frequency signal having a second frequency to be provided to the phase and frequency detector as its second input frequency signal, the VCO comprising at least one first varactor controlled by the feedback signal, a first inductor connected in parallel with the first varactor, at least one second inductor selectively connected to the first varactor and the first inductor by the band select signal, and at least one second varactor controlled by the frequency adjust signal and selectively connected to the first varactor and the first inductor by the band select signal; whereby the phase and frequency detector, the filter and compensation circuit and the VCO form a phase lock loop to lock the second frequency to the first frequency. - View Dependent Claims (12, 13)
-
-
14. A method of generating a phase locked frequency signal, comprising:
-
providing a voltage controlled frequency signal having a second frequency using a voltage controlled oscillator (VCO), the VCO comprising at least one first varactor and at least one second varactor connected to the first varactor, the second frequency being dependant on both the first and second varactors; detecting the frequency and phase information contained in the voltage controlled frequency signal and a frequency reference signal having a first frequency to generate an output error signal based on the detected information; passing the error signal through a filter and compensation circuit comprising a first low-pass filter to provide a first feedback signal and a second low pass filter to provide a second feedback signal; controlling the first varactor in the VCO using the first feedback signal to vary the second frequency; generating a frequency adjust signal based on the second feedback signal; and controlling the capacitance of the second varactor using the frequency adjust signal. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
-
-
22. A method of generating a band-selectable phase locked frequency signal, comprising:
-
providing a voltage controlled frequency signal having a second frequency using a voltage controlled oscillator (VCO), the VCO comprising at least one first varactor and a first inductor connected in parallel; detecting the frequency and phase information contained in the voltage controlled frequency signal and a frequency reference signal having a first frequency to generate an output error signal based on the detected information; processing the error signal to provide a first and a second feedback signal; controlling the first varactor in the VCO using the first feedback signal to vary the second frequency; providing a band select signal; selectively connecting or disconnecting at least one second inductor to the first varactor and the first inductor in the VCO based on the band select signal to change the second frequency; generating a frequency adjust signal based on the second feedback signal; and selectively connecting or disconnecting at least one second varactor to the first varactor and the first inductor in the VCO based on the band select signal; and controlling the capacitance of the second varactor connected to the first varactor and the first inductor using the frequency adjust signal. - View Dependent Claims (23, 24)
-
Specification