Frequency conversion module including emitter follower mixer

Claim 2

A direct current coupled frequency conversion circuit for a radio receiver having a first stage for translating a signal of a first frequency, and an intermediate frequency stage for amplifying a signal of a second lower frequency, and which receiver has a voltage supply for providing an operating voltage for the receiver which varies over a substantial range, such frequency conversion circuit converting the signal of the first frequency to a signal of the second frequency and including in combination, a semiconductor device including transistor means having base, emitter and collector electrodes, circuit means connected to said electrodes of said transistor means and to the voltage supply to form an emitter follower circuit, input means connected to said emitter follower circuit for applying the signal of said first frequency thereto, and oscillator means for producing a signal of a third frequency coupled to said emitter follower circuit, said emitter follower circuit being constructed to heterodyne said signals of said first and third frequencies to produce a signal of said second frequency.

Claim 3

The direct current coupled frequency conversion circuit of claim 1 wherein said oscillator means is a semiconductor crystal controlled oscillator of the Colpitts type.

Claim 4

The direct current coupled frequency conversion circuit of claim 1 wherein said semiconductor device further includes first transistor amplifier means having an input adapted to receive said first frequency signal and an output, said output being coupled to said emitter follower circuit, said first frequency signal being applied to One of said first amplifier input and said input means to provide a predetermined amplitude of said signal of said second frequency.

Claim 5

The direct current coupled frequency conversion circuit of claim 3 wherein said semiconductor device further includes second transistor amplifier means coupled to said emitter follower circuit for amplifying said second frequency signal.

Claim 6

The direct current coupled frequency conversion circuit of claim 3 wherein said semiconductor device further includes direct current coupled feedback circuit means coupled between said emitter follower circuit and said first amplifier means, said feedback circuit means cooperating with the voltage supply to apply stabilized bias voltages to said first amplifier means and said emitter follower circuit when the receiver voltage varies over said voltage range.

Claim 7

The direct current coupled frequency conversion circuit of claim 5 wherein said oscillator means includes a plurality of portions and wherein said first amplifier means, said emitter follower circuit, said direct current coupled feedback circuit means, and predetermined portions of said oscillator means are formed into a single integrated circuit chip.

Claim 8

The direct current coupled frequency conversion circuit of claim 6 wherein said single integrated circuit chip further includes an extra width isolation diffusion barrier for isolating said predetermined portions of said oscillator means from said first amplifier means, said emitter follower circuit, and said direct current coupled feedback circuit means.

Claim 9

The direct current coupled frequency conversion circuit of claim 3 wherein said first amplifier means includes first and second transistor means of the same conductivity type, said transistor means each having base, emitter and collector electrodes, means coupled to said electrodes of said first transistor means forming a common emitter circuit, means coupled to said electrodes of said second transistor means forming a common base circuit, said first and second transistor means being coupled together to form a cascode amplifier circuit, the base electrode of said first transistor means being adapted to receive said first frequency signal, the collector electrode of said second transistor means adapted to couple said amplified first frequency signal to said emitter follower circuit.

Claim 10

The direct current coupled frequency conversion circuit of claim 3 wherein said first amplifier means includes first and second transistor means, of the same conductivity type, each having base, emitter and collector electrodes, the base electrode of said first transistor means being adapted to receive said first frequency signal, the emitter electrode of said first transistor means being coupled to a first potential, the collector electrode of said first transistor means being coupled to the emitter electrode of said second transistor means, first reactance means coupling the base electrode of said second transistor means to said first potential, said collector electrode of said second transistor means adapted to couple the amplified first frequency signal to said emitter follower circuit.

Claim 11

A direct current coupled frequency conversion circuit for a radio receiver having a first stage for translating a signal of a first frequency, and an intermediate frequency stage for amplifying a signal of a second lower frequency, and which receiver has a voltage supply with first and second terminals for providing an operating voltage therebetween which varies over a substantial range, such frequency conversion circuit converting the signal of the first frequency to a signal of the second frequency and including in combination, first amplifier means having an input and an output, semiconductor means forming an emitter follower circuit having an input coupled to said output of said first amplifier means, oscillator means producing a signal of a third frequency coupled to said input of said emitter follower circuit, means applying a signal of the first frequency to one of said input of said first amplifier means and said input of said emitter follower circuit, said emitter follower circuit heterodyning said signals of first and third frequencies to produce a signal of said second frequency, direct current coupled feedback means coupled between said emitter follower circuit and said first amplifier means, bias circuit means coupled to the voltage supply and to said feedback means for applying a stabilized bias voltage to said first amplifier means and said emitter follower circuit in the presence of variations in the operating voltage over said voltage range, and second amplifier means coupled to said emitter follower circuit for amplifying said second frequency signal.

Claim 12

A direct current coupled frequency conversion circuit for a radio receiver having a first stage for translating a signal of a first frequency, and an intermediate frequency stage for amplifying a signal of a second lower frequency, and which receiver has a voltage supply with first and second terminals for providing an operating voltage therebetween which varies over a substantial range, such frequency conversion circuit converting the signal of the first frequency to a signal of the second frequency and including in combination, first amplifier means having an input and an output, semiconductor means forming an emitter follower circuit having an input coupled to said output of said first amplifier means, oscillator means producing a signal of a third frequency coupled to said input of said emitter follower circuit, means applying a signal of the first frequency to one of said input of said first amplifier means and said input of said emitter follower circuit, said emitter follower circuit heterodyning said signals of first and third frequencies to produce a signal of said second frequency, direct current coupled feedback means coupled between said emitter follower circuit and said first amplifier means, bias circuit means coupled to the voltage supply and to said feedback means for applying a stabilized bias voltage to said first amplifier means and said emitter follower circuit in the presence of variations in the operating voltage over said voltage range, and second amplifier means coupled to said emitter follower circuit for amplifying said second frequency signal.

Claim 13

The direct current coupled frequency conversion circuit of claim 10 wherein said direct current coupled feedback means includes, first transistor means direct current coupled to said emitter follower circuit and adapted to receive therefrom a signal varying with a change in the operating voltage, said first transistor means developing a first bias voltage and being adapted to produce a change in said first bias voltage in response to said signal, second transistor means coupled between the first transistor means and the first amplifier means for coupling said first bias voltage to said first amplifier means to change the operation thereof, said first amplifier means being direct current coupled to said emitter follower circuit whereby operation of said emitter follower circuit varies in accordance with the variation in said first bias voltage to reduce said signal.

Claim 14

The direct current coupled frequency conversion circuit of claim 10 wherein said semiconductor means includes transistor means having base, emitter and collector electrodes, the collector electrode being coupled to the voltage supply, the base electrode being adapted to receive said first and third frequency signals, said first and third frequency signals being heterodyned in said semiconductor means to produce said second frequency signal, the emitter electrode of said transistor means being adapted to couple said second frequency signal to the second amplifier means.

Claim 15

The direct current coupled frequency conversion circuit of claim 12 wherein said emitter follower circuit further includes reactance means coupled to the emitter electrode of said semiconductor means, said reactance means substantially reducing the amplitude of said first and third frequency signals in relation to said second frequency signal at said emitter electrode, said reactance means further acting to prevent oscillation in said second amplifier means.

Claim 16

The direct current coupled frequency conversion circuit of claim 12 wherein said emitter follower circuit further includes first capacitive reactance means and inductive reactance means in series combination coupled to the base electrode of said semiconductor means in said emitter follower circuit, said series combination acting to form a series resonant circuit at said second frequency for improving the efficiency of said emitter follower circuit, and second capacitance means in parallel with the series combination of said inductance means and first capacitance means, said parallel combination acting to form an antiresonant circuit at said first frequency, for decreasing said emitter follower circuit sensitivity to undesired signals.

Claim 17

A direct current coupled frequency conversion circuit for converting a first frequency signal to a second frequency signal, and constructed as a single integrated circuit chip, including in combination, first input means adapted to receive a third frequency signal from an oscillator, first amplifier means having an input and output with substantial isolation therebetween means applying said first frequency signal to one of said first amplifier input and said first input means, mixer means including transistor means having base, emitter and collector electrodes, and means connected to said electrodes to form an emitter follower circuit, said mixer means having an input and a low impedance output, said mixer means input being coupled to said first input means and said first amplifier output and being operative to heterodyne in said emitter follower circuit said first and third frequency signals coupled thereto to produce said second frequency signal, and second amplifier means coupled to said mixer means output for amplifying said second frequency signal, said mixer means output acting to attenuate said first and third frequency signals and to prevent said second amplifier means from oscillating.

Claim 18

A direct current coupled frequency conversion circuit for converting a first frequency signal to a second frequency signal, and constructed as a single integrated circuit chip, including in combination, first input means adapted to receive a third frequency signal from an oscillator, first amplifier means having an input and output with substantial isolation therebetween means applying said first frequency signal to one of said first amplifier input and said first input means, mixer means including transistor means having base, emitter and collector electrodes, and means connected to said electrodes to form an emitter follower circuit, said mixer means having an input and a low impedance output, said mixer means input being coupled to said first input means and said first amplifier output and being operative to heterodyne in said emitter follower circuit said first and third frequency signals coupled thereto to produce said second frequency signal, and second amplifier means coupled to said mixer means output for amplifying said second frequency signal, said mixer means output acting to attenuate said first and third frequency signals and to prevent said second amplifier means from oscillating.

Claim 19

The direct current coupled frequency conversion circuit of claim 15 wherein said mixer means includes a capacitive reactance connected to said mixer means output for attenuating said first and third frequency signals.

Claim 20

The direct current coupled frequency conversion circuit of claim 15 wherein said mixer input includes first capacitive reactance means and inductive reactance means in series combination, said series combination acting to form a series resonant circuit at said second frequency for improving the efficiency of said mixer means, second capacitance means in parallel with said series combination of said inductance means and first capacitance means, said parallel combination acting to form an antiresonant circuit at said first frequency for preventing said first frequency signal from being coupled to said mixer output.

Claim 21

The direct current coupled frequency conversion circuit of claim 15 further including an oscillator having a plurality of portions with predetermined ones of said portions of said oscillator on said integrated circuit chip, said oscillator being coupled to one of said input means and said first amplifier means input, whereby said first amplifier means, said mixer means, said second amplifier means, and said predetermined portions of said oscillator are constructed in a single integrated circuit chip.