Dual band transmitter for a cellular phone comprising a PLL

In a cellular phone for a mobile communications system, a method for generating at least two output frequency ranges from a phase locked loop (PLL) having a phase detector, a loop filter, and a single voltage-controlled oscillator (VCO), the method comprising the steps of:

• multiplying an output of the VCO by a predetermined value to produce a multiplied output;
• selecting a desired output frequency;
• selectably feeding back to the phase detector one of the output of the VCO and the multiplied output, based upon the selected desired output frequency, wherein when the output of the VCO is selected, the output of the VCO is fed back, and when the multiplied output is selected, the multiplied output is fed back;
• and
• setting a gain of at least one of the phase detector or the loop filter according to the selected output frequency.

A dual band transmitter for a wireless phone, comprising:

• a first power amplifier, said first power amplifier having a first input for a first signal in a first radio frequency band, and having a first output for an amplified first signal, said first output being connectable to an antenna;
• a second power amplifier, said second power amplifier having a second input for a second signal in a second radio frequency band and a second output for an amplified second signal, said second output being connectable to said antenna;
• and
• a phase locked loop (PLL) configured to generate two or more output frequency ranges, and connected to the first and second power amplifiers, the PLL comprising:
• a first frequency divider configured to divide a frequency signal by a value N;
• a phase detector responsive to an output of the first divider;
• a loop filter responsive to an output of the phase detector;
• a voltage-controlled oscillator (VCO) responsive to an output of the loop filter and providing said first signal;
• a frequency multiplier responsive to an output to the VCO and providing said second signal;
• a band-switch having a first input responsive to the output of the VCO, a second input responsive to an output of the frequency multiplier, and a third input responsive to a control signal to select for output from said band-switch one of the first and second inputs;
• a mixer having two inputs, one mixer input responsive to the output of the band-switch and a second mixer input responsive to a radio frequency signal;
• a second frequency divider configured to divide an input frequency by a value M, the second divider responsive to an output of the mixer, and an output of the second frequency divider providing an input to the phase detector.

A dual band transmitter for a wireless phone, comprising:

• a first power amplifier, said first power amplifier having a first input for a first signal in a first radio frequency band, and a first output for an amplified first signal, said first output being connectable to an antenna;
• a second power amplifier, said second power amplifier having a second input for a second signal in a second radio frequency band and a second output for an amplified second signal, said second output being connectable to said antenna;
• and
• a phase locked loop (PLL) configured to generate two or more output frequency ranges, and connected to the first and second power amplifiers, the PLL comprising:
• a first frequency divider configured to divide a frequency signal by a value N;
• a phase detector responsive to an output of the first divider;
• a loop filter responsive to an output of the phase detector;
• a voltage-controlled oscillator (VCO) responsive to an output of the loop filter and providing said first signal;
• at least one frequency multiplier responsive to an output to the VCO and providing said second signal;
• a mixer having two inputs, one mixer input responsive to the output of the VCO and a second mixer input responsive to a local oscillator signal;
• a second frequency divider configured to divide an input frequency by a value M and connected to an output of the mixer, and an output of the second frequency divider providing an input to the phase detector;
• and
• a selector connected to the output of the at least one frequency multiplier, the selector configured to select an output frequency.

A cellular phone for a mobile communications system, said phone being operable in a first radio frequency band and a second radio frequency band, comprising a dual band transmitter and an antenna, said dual band transmitter comprising a phase-locked loop (PLL) which can generate two or more output frequency ranges, the PLL comprising:

• a first frequency divider configured to divide a frequency signal by a value N;
• a phase detector responsive to an output of the first frequency divider;
• a loop filter responsive to an output of the phase detector;
• a voltage-controlled oscillator (VCO) responsive to an output of the loop filter;
• at least one frequency multiplier responsive to an output of the VCO;
• a mixer having two inputs, one mixer input responsive to the output of the VCO and a second mixer input responsive to a local oscillator signal;
• a second frequency divider configured to divide an input frequency by a value M and connected to an output of the mixer, an output of the second divider providing an input to the phase detector;
• and
• a selector connected to the output of the at least one frequency multiplier, the selector configured to select an output frequency.

In a cellular phone for a mobile communications system, a method for generating at least two output frequency ranges from a phase locked loop (PLL) having a single voltage controlled oscillator (VCO), an adjustable first frequency divider which divides by a value N, a second frequency divider which divides by a value M, a phase detector, and a loop filter, the method comprises the steps of:

• multiplying an output of the VCO by a predetermined value to produce a multiplied output frequency;
• selecting a desired output frequency of one of the VCO output and the multiplied output frequency;
• and
• adjusting the values of the first frequency divider such that a ratio N/M equals the value of the predetermined value when the multiplied output is selected, and adjusting the ratio N/M equal to the value "1" when the VCO output is selected.

A dual band transmitter for a wireless phone, comprising:

• a first power amplifier, said first power amplifier having a first input for a first signal in a first radio frequency band, and a first output for an amplified first signal, said first output being connectable to an antenna;
• a second power amplifier, said second power amplifier having a second input for a second signal in a second radio frequency band and a second output for an amplified second signal, said second output being connectable to said antenna;
• and
• a phase locked loop (PLL) which can generate two or more output frequency ranges, the PLL comprising:
• a voltage-controlled oscillator (VCO) having a first output connected to said first power amplifier, said VCO generating said first signal;
• a frequency multiplier having an input connected to said first output of the VCO and a second output connected to said second power amplifier, said frequency multiplier receiving said first signal and generating said second signal.

In a cellular phone for a mobile communications system, a method for generating at least two output frequency ranges from a phase locked loop (PLL) having a phase detector, a loop filter, and a single voltage-controlled oscillator (VCO), the method comprising the steps of:

• multiplying an output of the VCO by a plurality of predetermined values to produce a plurality of multiplied outputs;
• selecting a desired output frequency;
• selectably feeding back to the phase detector one of the outputs of the VCO and one of the plurality of multiplied outputs, based upon the selected desired output frequency, wherein when the output of the VCO is selected, the output of the VCO is fed back, and when the multiplied output is selected, the multiplied output is fed back;
• and
• setting a gain of at least one of the phase detector or the loop filter according to the selected output frequency.

In a dual band transmitter for a wireless phone, a method for generating two output frequency ranges from a phase locked loop (PLL) having a single voltage controlled oscillator (VCO), the method comprising the steps of:

• multiplying an output of the VCO by a predetermined value to produce a multiplied output frequency;
• selecting a desired output frequency of one of the VCO output and the multiplied output frequency;
• and
• adjusting a value of a first divider that divides a frequency signal by the value N and inputs it to a phase detector and a value M of a second divider that divides a signal responsive to the multiplied output by the value M and inputs it to the phase detector such that a ratio N/M equals a predetermined value when the multiplied output is selected, and adjusting the ratio N/M equal to the value "1" when the VCO output is selected.

In a dual band transmitter for a wireless phone, a method for generating two output frequency ranges from a phase locked loop (PLL) having a single voltage controlled oscillator (VCO), the method comprising the steps of:

• multiplying an output of the VCO by a predetermined value to produce a multiplied output frequency;
• selecting a desired output frequency of one of the VCO output and the multiplied output frequency;
• and
• adjusting a value of a first divider that divides a frequency signal by the value N and inputs it to a phase detector and a value M of a second divider that divides a signal responsive to the multiplied output by the value M and inputs it to the phase detector such that a ratio N/M equals a predetermined value when the multiplied output is selected, adjusting the ratio N/M equal to the value "1" when the VCO output is selected, and adjusting the value of M, a gain of the phase detector and/or a gain of a loop filter receiving a signal from the phase detector.

In a dual band transmitter for a wireless phone, a method for generating two output frequency ranges from a phase locked loop (PLL) having a single voltage controlled oscillator (VCO), the method comprising the steps of:

• multiplying an output of the VCO by a plurality of predetermined values to produce a plurality of multiplied output frequencies;
• selecting a desired output frequency of one of the VCO output and one of the plurality of multiplied output frequencies;
• and
• adjusting a value of a first divider that divides a frequency signal by the value N and inputs it to a phase detector and a value M of a second divider that divides a signal responsive to the multiplied output by the value M and inputs it to the phase detector such that a ratio N/M equals a predetermined value corresponding to the selected output frequency when the multiplied output is selected, and adjusting the ratio N/M equal to the value "1" when the VCO output is selected.