Master frequency generator

Abstract

A system is provided for generating multiple frequencies in a specified frequency band, with a specified step size between frequencies, in which the spectral purity of the frequencies is assured. The switching speed between frequencies is very fast, limited only by the speed of the switches used. In one embodiment, only five tones are generated as the base for the rest of the synthesis, in which the relationship of the five tones is f 0 +/−⅛f 0 and +/− 1/16f 0 . The subject system may be utilized in air defense systems for generating the transmit channels to be able to permit a missile seeker to transmit a signal at the appropriate frequency. In one embodiment, spectral purity is achieved by providing a number of stages of up converting, expanding, and dividing down of an input signal.

1. A system for generating hundreds of frequencies for use in the generation of RF signals in which the RF signals are to be spectrally pure, and in which the frequencies are both preselected and pre-selectable, comprising:
 a master frequency generator for generating five tones; and,  
 means for mixing selected ones of said five tones for generating one of said preselected frequencies.  
 
     
     
       2. The system of  claim 1 , wherein the relationship between said five tones is
   f 0 , f 0 +⅛f 0 , f 0 −⅛f 0  + 1/16f 0 , and f 0 − 1/16f 0 .  
 
     
     
       3. The system of  claim 1 , wherein said master frequency generator includes a reference oscillator, a divide-by-8 divider coupled to the output of said reference oscillator, a divide-by-2 divider coupled to the output of said divide-by-8 divider, a combiner for combining the output of said divide-by-8 divider and said divide-by-2 divider, a mixer for mixing the output of said combiner and said reference frequency oscillator, and a means coupled to the output of said mixer for separating the output of said mixer into four of said five tones, the fifth of said tones being the output of said reference oscillator. 
     
     
       4. The system of  claim 3 , wherein said means for separating the output of said mixer includes a quadraplexer. 
     
     
       5. The system of  claim 1 , and further including a missile seeker having a millimeter radar transmitter for transmitting radar signals in a number of different frequency channels, and wherein said mixing means includes it channel synthesizer capable of generating hundreds of frequencies from said five tones, a reference oscillator and an up-converter coupled to said reference oscillator and said channel synthesizer for generating RF energy having a frequency in the channel specified by said channel synthesizer. 
     
     
       6. The system of  claim 1 , wherein said mixing means includes means for up-converting, expanding and dividing down an input signal to reduce spurs and thus achieve spectral purity. 
     
     
       7. A system, comprising:
   a master frequency generator configured to generate a plurality of tones;        a distribution unit - configured to receive a plurality of inputs corresponding to the plurality of tones, wherein the distribution unit is configured to selectively transmit, at each of a plurality of outputs of the distribution unit, one of the plurality of tones as one of a plurality of output frequencies;        a plurality of frequency dividers, each of which is configured to receive one of the plurality of output frequencies, wherein each of the plurality of frequency dividers is configured to output a respective divided frequency;        a plurality of mixers, wherein the number of the plurality of mixers equals the number of the plurality of frequency dividers, wherein each of the plurality of mixers is configured to receive a divided frequency outputted by a respective one of the plurality of frequency dividers, wherein each of the plurality of mixers is configured to receive one of the plurality of output frequencies, and wherein each of the plurality of mixers is configured to output a respective mixed frequency; and        a combining unit including at least one divider and at least one mixer, wherein the combining unit is configured to receive a respective mixed frequency from each of the plurality of mixers, wherein the combining unit is configured to output a selected one of a plurality of substantially spur - free frequencies.      
     
     
       8. A system in accordance with  claim 7 , wherein the number of the plurality of outputs of the distribution unit is an even number.  
     
     
       9. A system in accordance with  claim 7 ,
   wherein the distribution unit has  4  outputs,        wherein the number of the plurality of frequency dividers is  2 , and        wherein the number of the plurality of mixers is  2 .      
     
     
       10. A system in accordance with  claim 7 ,
   wherein the at least one frequency divider in the combining unit is  2  dividers, and        wherein the at least one mixer in the combining unit is  1  mixer.      
     
     
       11. A system in accordance with  claim 7 , wherein the master frequency generator includes a master frequency oscillator configured to generate a master frequency and further includes at least one frequency divider.  
     
     
       12. A system, comprising:
   a master frequency generator configured to generate a plurality of tones;        a distribution unit configured to receive a plurality of inputs corresponding to the plurality of tones, wherein the distribution unit is configured to selectively transmit, at each of a plurality of outputs of the distribution unit, one of the plurality of tones as one of a plurality of output frequencies;        a plurality of divider/mixer units, each of which includes at least one divider and at least one mixer, wherein each of the plurality of divider/mixer units is configured to receive one of the plurality of output frequencies, and wherein each of the plurality of divider/mixer units is configured to output a divided and mixed frequency; and        a combining unit including at least one divider and at least one mixer, wherein the combining unit is configured to receive a divided and mixed frequency outputted from a respective one of the plurality of divider/mixer units, wherein the combining unit is configured to output a selected one of a plurality of substantially spur - free frequencies.      
     
     
       13. A system in accordance with  claim 12 ,
   wherein the at least one divider in each of the plurality of divider/mixer units is  1  divider, and        wherein the at least one mixer in each of the plurality of divider/mixer units is  1  mixer.      
     
     
       14. A system in accordance with  claim 12 ,
   wherein each of the plurality of divider/mixer units is configured to divide a received first input and mix the divided first input with a received second input.      
     
     
       15. A system in accordance with  claim 12 , wherein the number of the plurality of outputs of the distribution unit is an even number.  
     
     
       16. A system in accordance with  claim 12 ,
   wherein the distribution unit has  4  outputs, and        wherein the number of the plurality of divider/mixer units is  2 .      
     
     
       17. A system in accordance with  claim 12 ,
   wherein the at least one divider in the combining unit is  2  dividers, and        wherein the at least one mixer in the combining unit is  1  mixer.      
     
     
       18. A system in accordance with  claim 12 , wherein the master frequency generator includes a master frequency oscillator configured to generate a master frequency and further includes at least one divider.  
     
     
       19. A method, comprising:
   a device generating five tones, the five tones having respective frequencies            f   o     ,       f   o     -       1   8     ⁢     f   o         ,       f   o     +       1   8     ⁢     f   o         ,       f   o     -       1   16     ⁢     f   o         ,         and   ⁢           ⁢     f   o       +       1   16     ⁢     f   o         ;               the device using the five generated tones to generate a plurality of frequencies, the number of said plurality of frequencies being greater than or equal to  100 ;        the device selecting one of the generated plurality of frequencies at which to emit radiation; and        the device using received reflections of the emitted radiation to change a heading of the device.      
     
     
       20. The method of  claim 19 , wherein the device is a missile.  
     
     
       21. The method of  claim 19 , wherein each of the plurality of frequencies is substantially spur- free, and wherein using the five generated tones to generate a plurality of frequencies includes providing different combinations of the five tones to a channel synthesizer.    
     
     
       22. A system, comprising:
   first means for generating a plurality of tones; and        second means for receiving different combinations of the plurality of tones and for generating a plurality of substantially spur - free frequencies therefrom.      
     
     
       23. The system of  claim 22 , wherein the first means is for generating at least five tones.