Method and apparatus for increasing the high frequency sensitivity response of a sampler frequency converter

A sampler frequency converter having a sensitivity response for providing an output signal having a frequency F.sub.OUT and an amplitude which varies as a function of (sin F.sub.IN)/F.sub.IN, where F.sub.IN is the frequency of an input signal applied thereto, comprising:

• a local oscillator means having a frequency F.sub.LO ;
• a step recovery diode means responsive to F.sub.LO for providing a pulse train having a pulse repetition rate F.sub.LO ;
• a balun transformer means for converting said pulse train to a positive pulse train and a negative pulse train;
• a first and a second sampler diode means, each of said diode means having an anode and a cathode;
• capacitor means for coupling said positive pulse train to said anode of said first sampler diode means and said negative pulse train to said cathode of said second sampler diode means;
• means for providing said input signal having said frequency F.sub.IN to a node located between said cathode of said first sampler diode means and said anode of said second sampler diode means;
• a bandpass filter means;
• capacitor means for coupling said anode of said first sampler diode means and said cathode of said second sampler diode means to said bandpass filter means;
• and
• means for forward biasing said first and said second sampler diode means when said frequency F.sub.IN is above a predetermined frequency such that sharp decreases in the amplitude of said output signal which occur as the frequency F.sub.IN of said input signal is changed occur at a lower frequency F.sub.IN of said input signal after said diodes are biased than before said diodes are biased.

A sampler frequency converter comprising:

• means including a diode circuit means having a plurality of diodes for providing in response to an input signal S.sub.IN having a frequency F.sub.IN and sampling pulses an output signal S.sub.OUT having a frequency F.sub.OUT which is defined by the relationship
• F.sub.OUT =.vertline.F.sub.IN .+-.N.times.F.sub.LO.vertline.
• and an amplitude which varies as a function of (sin x)/x where x=F.sub.IN ;
• and
• means for forward biasing said diodes when the frequency F.sub.IN of said input signal is above a predetermined frequency whereby the nulls which occur in said (sin x)/x relationship occur at a lower frequency after said biasing than before said biasing to thereby increase the sensitivity of said sampler frequency converter at frequencies above said predetermined frequency.

A sampler frequency converter comprising:

• means including a diode circuit means having a plurality of diodes for sampling an input signal S.sub.IN having a frequency F.sub.IN for providing an output signal S.sub.OUT having a frequency F.sub.OUT which is defined by the relationship
• F.sub.OUT =.vertline.F.sub.IN .+-.N.times.F.sub.LO .vertline.
• and an amplitude which varies as a function of (sin x)/x where x=F.sub.IN, said sampling means having a sampling period;
• and
• means responsive to said frequency F.sub.IN of said input signal S.sub.IN for increasing said sampling period when said frequency F.sub.IN of said input signal S.sub.IN is above a predetermined frequency.