Amplifier for correcting group time delay of electrical signals and an intermediate frequency amplifier stage for radio equipment comprising an amplifier of this kind

Claim 2

Amplifier for correcting group time delay of electrical signals, comprising first and second DC voltage supply terminals, an input transistor having a collector, an emitter and a base and to which a signal to be amplified is applied, an output transistor having a collector, an emitter and a base, a group time delay corrector network, at least one capacitor and a choke, wherein said input and output transistors have respective collector-emitter junctions connected in series between said first and second terminals, said input and output transistors are configured as common-emitter voltage amplifiers, said collector of said input transistor is connected to said base of said output transistor through said group time delay corrector network, and said emitter of said output transistor is connected to one of said terminals through said at least one capacitor and connected to said collector of said input transistor through said choke.

Claim 3

Amplifier according to claim 1, wherein said group time delay corrector network comprises an autotransformer with a ratio of 1/2 consisting of two windings connected in series, a resistor connected between the non-commoned ends of said autotransformer windings, and an inductor and a capacitor connected in series between the commoned ends of said autotransformer windings and one of said terminals.

Claim 4

Amplifier according to claim 2, wherein said inductor and said capacitor are of variable impedance.

Claim 5

Amplifier according to claim 2, further comprising a matching circuit and wherein said group time delay corrector network has an input connected to said collector of said input transistor through said matching circuit, said output transistor has a base-emitter region, said group time delay network has an output connected to said base-emitter region, and the values Z A and Z B of the impedances of said matching circuit and said base-emitter region and the value ρ of said resistor of said group time delay corrector cell are such that |Z.sub.A |>ρ>|Z.sub.B | and 4·Z.sub.A ·Z.sub.B =ρ.sup.2.

Claim 6

Amplifier according to claim 1, further comprising a single voltage divider bridge comprising resistors connected in series between said first and second terminals and adapted to produce DC bias voltages for said bases of said input and output transistors.

Claim 7

Amplifier according to claim 1, further comprising an emitter resistor for said input transistor and wherein said emitter of said input transistor is connected to said second terminal through said emitter resistor.

Claim 8

Amplifier according to claim 6, further comprising a decoupling capacitor connected in parallel with said emitter resistor.

Claim 9

Amplifier according to claim 1, further comprising a feedback circuit connected between said collector and said base of said input transistor.

Claim 10

Amplifier according to claim 1, further comprising a feedback circuit connected between said collector and said base of said output transistor.

Claim 11

Radio amplifier stage having an input and an output and comprising a plurality of group time delay correcting amplifiers, a plurality of variable attenuators whereby said amplifiers are connected in series, and an automatic gain control circuit connected to said output of said amplifier stage and adapted to control the attenuation of said attenuators, wherein each group time delay correcting amplifier comprises first and second DC voltage supply terminals, an input transistor having a collector, an emitter and a base and to which a signal to be amplified is applied, an output transistor having a collector, an emitter and a base, a group time delay corrector network, at least one capacitor and a choke, wherein said input and output transistor have respective collector-emitter junctions connected in series between said first and second terminals, said input and output transistors are configured as common-emitter voltage amplifiers, said collector of said input transistor is connected to said base of said output transistor through said group time delay corrector network, and said emitter of said output transistor is connected to one of said terminals through said at least one capacitor and connected to said collector of said input transistor through said choke.

Claim 12

Radio amplifier stage having an input and an output and comprising a plurality of group time delay correcting amplifiers, a plurality of variable attenuators whereby said amplifiers are connected in series, and an automatic gain control circuit connected to said output of said amplifier stage and adapted to control the attenuation of said attenuators, wherein each group time delay correcting amplifier comprises first and second DC voltage supply terminals, an input transistor having a collector, an emitter and a base and to which a signal to be amplified is applied, an output transistor having a collector, an emitter and a base, a group time delay corrector network, at least one capacitor and a choke, wherein said input and output transistor have respective collector-emitter junctions connected in series between said first and second terminals, said input and output transistors are configured as common-emitter voltage amplifiers, said collector of said input transistor is connected to said base of said output transistor through said group time delay corrector network, and said emitter of said output transistor is connected to one of said terminals through said at least one capacitor and connected to said collector of said input transistor through said choke.