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US 6,018,275 AGranted
Phase locked loop with down-conversion in feedback path
AssigneeNokia Mobile Phones Ltd.
InventorsAlan Christopher Perrett, Kenneth Peter Mason
Life of this patent
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AssigneeNokia Mobile Phones Ltd.
InventorsAlan Christopher Perrett, Kenneth Peter Mason
Estimating the term…
A transmitter and a phase locked loop (30) for a transmitter are disclosed. The phase locked loop (30) upconverts the frequency of a baseband signal to a frequency for radio transmission. As well as the usual components, the phase locked loop (30) comprises a modulator (39) for modulating a baseband signal (f.sub.bb) onto a carrier (f.sub.ref /R) and forwarding the resultant modulated signal (f.sub.c) to one of the inputs of the phase detector (33). It also comprises a low pass filter (38) in its forward path between the phase detector (33) and the voltage controlled oscillator (34) for passing signals having baseband signal frequencies. A mixer (35) and main frequency divider (36) are provided in the feedback path to downconvert the transmit signal (f.sub.tx). This low division eliminates large amounts of multiplicative noise within the loop bandwidth, and therefore enables a large loop bandwidth to be used. Consequently, the settling time of the phase locked loop is improved.
A phase locked loop for upconverting and scaling the frequency of a baseband signal to a frequency for radio transmission, the phase locked loop comprising:
A radio transmitter comprising a phased locked loop for generating from a baseband signal a signal to be transmitted by the transmitter, wherein the phase locked loop comprises:
A phase locked loop for upconverting and scaling the frequency of a baseband signal to a frequency for radio transmission, the phase locked loop comprising:
A radio transmitter comprising a phase locked loop for generating from a baseband signal a signal to be transmitted by the transmitter, wherein the phase locked loop comprises:
A phase locked loop for upconverting and scaling the frequency of a baseband signal to a frequency for radio transmission, the phase locked loop comprising:
A phase locked loop for upconverting and scaling the frequency of a baseband signal to a frequency for radio transmission, the phase locked loop comprising:
A phase locked loop for altering the frequency of a baseband signal to a frequency for radio transmission, the phase locked loop comprising:
A phase locked loop suitable for use in a communication device, comprising:
Dependencies are inferred from the claim text.