Apparatus and method for frequency translation in a communication device
First Claim
1. An apparatus for converting a baseband modulated in phase (I) component, and a baseband modulated quadrature (Q) component to an intermediate frequency (IF) signal, the apparatus comprising:
- a controller, having an input for receiving a clock signal with a predetermined clock cycle rate, operable for outputting a first and a second predetermined control signal based on a predetermined number of clock cycles;
a first multiplying digital to analog conversion (MDAC) unit receiving the first predetermined control signal and the baseband modulated I component, being operable for stepping the baseband modulated I component by a stepped sinewave having predetermined step sizes to output a sinewave modulated I signal based on the first predetermined control signal;
a second MDAC unit receiving the second predetermined control signal and the baseband modulated Q component, being operable for stepping the baseband modulated Q component by a stepped cosinewave having predetermined step sizes to output a cosinewave modulated Q signal based on the second predetermined control signal; and
a summing unit receiving the first and the second MDAC output signals and being operable for summing the output signals to form the IF signal.
2 Assignments
0 Petitions
Accused Products
Abstract
A frequency translation device in a first embodiment includes a plurality of multiplying digital-to-analog converters (MDACs) that multiply an input signal by phase shifted digital sinewave approximation signals to perform frequency translation. In the preferred embodiment the input includes inphase and quadrature phase components, one of which is multiplied by a digital sinewave approximation and the other is multiplied by a digital cosinewave approximation. The use of the multiple MDACs with differing sinewave approximation signals provides a signal that multiplies the input signal such that the effects of odd harmonics at an output are mitigated while the advantages of a traditional switching mixer are retained.
-
Citations
14 Claims
-
1. An apparatus for converting a baseband modulated in phase (I) component, and a baseband modulated quadrature (Q) component to an intermediate frequency (IF) signal, the apparatus comprising:
-
a controller, having an input for receiving a clock signal with a predetermined clock cycle rate, operable for outputting a first and a second predetermined control signal based on a predetermined number of clock cycles; a first multiplying digital to analog conversion (MDAC) unit receiving the first predetermined control signal and the baseband modulated I component, being operable for stepping the baseband modulated I component by a stepped sinewave having predetermined step sizes to output a sinewave modulated I signal based on the first predetermined control signal; a second MDAC unit receiving the second predetermined control signal and the baseband modulated Q component, being operable for stepping the baseband modulated Q component by a stepped cosinewave having predetermined step sizes to output a cosinewave modulated Q signal based on the second predetermined control signal; and a summing unit receiving the first and the second MDAC output signals and being operable for summing the output signals to form the IF signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A method for converting a baseband modulated in phase (I) component, and a baseband modulated quadrature (Q) component to an intermediate frequency (IF) signal, the method comprising the steps of:
-
receiving, by a controller, a clock signal with a predetermined clock cycle rate and outputting a first and a second predetermined control signal based on a predetermined number of clock cycles; receiving, by a first multiplying digital to analog conversion (MDAC) unit, the first predetermined control signal and the baseband modulated I component, and stepping the I component by a stepped sinewave based on the first control signal to output a first MDAC output signal approximating a sinusoid having a first phase; receiving, by a second MDAC unit, the second predetermined control signal and the baseband modulated Q component, and stepping the Q component by a stepped cosinewave based on the second control signal to output a second MDAC output signal approximating the sinusoid having a second phase; and receiving the first and the second MDAC output signals in a summing unit and summing the first and the second MDAC output signals to form the IF signal. - View Dependent Claims (9, 10, 11, 12, 13)
-
-
14. A method of frequency translation comprising:
-
receiving, by a controller, a clock signal with a predetermined clock cycle rate and outputting predetermined control signals based on a predetermined number of clock cycles; receiving, by a multiplying digital to analog conversion (MDAC) unit, plural input signals having a same modulation and the control signals, and stepping the input signals based on the control signals to output plural MDAC output signals each approximating a sinusoid of same amplitude and period but differing in phase; and receiving the MDAC output signals in a summing unit and summing the MDAC output signals to form a frequency translated output signal.
-
Specification