High-speed digital-to-RF-converter
AssigneeHughes Aircraft Company
InventorsRonald E. Sorace, Victor S. Reinhardt, Steven A. Vaughn
Life of this patent
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Abstract
A plurality of biphase modulators (42) each modulate a sinusoidal radio frequency signal based upon a corresponding one of a plurality of bits contained in a time-dependent data word. The biphase modulators (42) form a plurality of biphase modulated signals which are communicated to a summing network (40). The summing network (40) contains a plurality of attenuators (44) which attenuate the modulated signals to form a plurality of attenuated signals. The summing network (40) combines the attenuated signals to form a radio frequency signal.
Claims8
A system for predistorting a digital signal and converting the digital signal to a radio frequency signal, the digital signal representative of a time-dependent data word having a plurality of bits, the system comprising:
- a plurality of biphase modulators, each of the biphase modulators modulating a sinusoidal radio frequency signal with a corresponding one of the bits to form a biphase modulated signal based upon the corresponding one of the bits, whereby the biphase modulators form a plurality of biphase modulated signals;
- and
- a summing network containing a plurality of variable attenuators having an attenuation dependent upon a transfer function of a communication channel, each of the attenuators responsive to a corresponding one of the biphase modulated signals, the attenuators attenuating the biphase modulated signals to form a plurality of attenuated signals, wherein the summing network combines the attenuated signals to form the radio frequency signal.
A system for converting a digital signal to a radio frequency signal, the digital signal having an inphase component and a quadrature component, the system comprising:
- a first shift register for generating a first time-dependent data word having a plurality of bits based upon the inphase component of the digital signal;
- a second shift register for generating a second time-dependent data word having a plurality of bits based upon the quadrature component of the digital signal;
- a first set of biphase modulators responsive to the first shift register, each of the biphase modulators of the first set modulating a first sinusoidal radio frequency signal with a corresponding one of the bits of the first time-dependent data word to form an inphase biphase modulated signal based upon the corresponding one of the bits of the first time-dependent data word, whereby the biphase modulators form a plurality of inphase biphase modulated signals;
- a second set of biphase modulators responsive to the second shift register, each of the biphase modulators of the second set modulating a second sinusoidal radio frequency signal with a corresponding one of the bits of the second time-dependent word to form a quadrature biphase modulated signal based upon the corresponding one of the bits of the second time-dependent data word, whereby the biphase modulators form a plurality quadrature biphase modulated signals;
- a first summing network containing a plurality of variable attenuators, each of the attenuators in the first summing network responsive to a corresponding one of the inphase biphase modulated signals, the attenuators attenuating the inphase biphase modulated signals to form a plurality of inphase attenuated signals:
- a second summing network containing a plurality of variable attenuators each of the attenuators in the second summing network responsive to a corresponding one of the quadrature biphase modulated signals, the attenuators attenuating the quadrature biphase modulated signals to form a plurality of quadrature attenuated signals;
- and
- a summer circuit combining the inphase and quadrature attenuated signals to form the radio frequency signal.
A method of predistorting a digital signal and converting the digital signal to a radio frequency signal, the digital signal representative of a time-dependent data word having a plurality of bits, the method comprising the steps of:
- forming a plurality of biphase modulated signals with a corresponding plurality of biphase modulators, wherein each of the biphase modulated signals is based upon a corresponding one of the bits and includes a sinusoidal radio frequency signal modulated with the corresponding one of the bits;
- attenuating each of the biphase modulated signals with an attenuation dependent upon a transfer function of a communication channel to form a plurality of attenuated signals;
- and
- combining the attenuated signals to form the radio frequency signal.
Dependencies are inferred from the claim text.