Method and apparatus for controlling RF spectral splatter into adjacent channels when activating an RF transmitter

Claim 2

An RF transmitter, comprising: an RF amplifier having a tuned output circuit; and means connected across an output of the RF amplifier for substantially eliminating interference in adjacent frequencies caused by activation of the RF amplifier when initially presented with an input RF signal.

Claim 3

A transmitter according to claim 1, wherein the means for substantially eliminating includes: a series-connected diode and first capacitor connected across the amplifier output; and a series-connected resistor and second capacitor connected across the first capacitor for providing a biasing current to the diode during initial activation of the RF amplifier by an input RF signal.

Claim 4

A transmitter according to claim 2, wherein the amplifier is a class-C amplifier and the diode is a PIN diode.

Claim 5

A transmitter according to claim 2, wherein a time constant of the biasing current is substantially longer than a rise time in which the amplifier would otherwise generate a full power output signal after initial activation.

Claim 6

A transmitter according to claim 2, further comprising: a second resistor in parallel with the second capacitor for discharging the capacitor when the transmitter is deactivated.

Claim 9

A method according to claim 6, wherein the generating step comprises charging a capacitor and said method further comprises: discharging said capacitor when the amplifier RF signal output is reduced.

Claim 10

A radio frequency transmitter comprising: a radio frequency amplifier for producing an amplified RF output signal; a passive RF transient suppression circuit coupled to said RF output signal for automatically retarding the rate at which the amplitude envelope of said RF output signal increases.

Claim 11

A radio frequency transmitter comprising: a radio frequency amplifier for producing an amplified RF output signal; a passive RF transient suppression circuit coupled to said RF output signal for automatically retarding the rate at which the amplitude envelope of said RF output signal increases.

Claim 12

A radio frequency transmitter comprising: a radio frequency amplifier having an input and an output; an envelope detector coupled to the amplifier output for detecting the amplitude envelope of radio frequency signals at the amplifier output; a transient control circuit coupled to the envelope detector for automatically generating a control signal during transient increases in said amplitude envelope; and a controllable radio frequency attenuator coupled to said control signal and to said amplifier output to automatically attenuate the output of said amplifier during said transient increases.

Claim 13

A radio frequency transmitter comprising: a radio frequency amplifier having an input and an output; an envelope detector coupled to the amplifier output for detecting the amplitude envelope of radio frequency signals at the amplifier output; a transient control circuit coupled to the envelope detector for automatically generating a control signal during transient increases in said amplitude envelope; and a controllable radio frequency attenuator coupled to said control signal and to said amplifier output to automatically attenuate the output of said amplifier during said transient increases.

Claim 14

A radio frequency transmitter as in claim 9, wherein: said envelope detector includes a series-connected PIN diode and first capacitance, said detector being RF shunt-connected across the amplifier output; and said transient control circuit includes a series-connected resistance and second capacitance, said control circuit being shunt-connected across said first capacitor.

Claim 15

A radio frequency transmitter as in claim 10, wherein said controllable radio frequency attenuator includes said PIN diode.

Claim 16

A radio frequency transmitter as in claim 10, further comprising: a static bleeder discharge resistance connected in shunt across said second capacitor.

Claim 17

An RF transmitter, comprising: an RF amplifier having a tuned output circuit; a series-connected diode and first capacitor connected across the amplifier output; and a series-connected resistor and second capacitor connected across the first capacitor for providing a biasing current to the diode during initial activation of the RF amplifier by an input RF signal.

Claim 18

An RF transmitter, comprising: an RF amplifier having a tuned output circuit; a series-connected diode and first capacitor connected across the amplifier output; and a series-connected resistor and second capacitor connected across the first capacitor for providing a biasing current to the diode during initial activation of the RF amplifier by an input RF signal.

Claim 21

A radio frequency transmitter, comprising: a radio frequency amplifier having an input and an output; an envelope detector coupled to the amplifier output for detecting an amplitude envelope of radio frequency signals at the amplifier output including a series-connected PIN diode and first capacitance connected across the amplifier output; a transient control circuit coupled to the envelope detector for automatically generating a control signal during transient increases in the amplitude envelope; and a controllable radio frequency attenuator coupled to the control signal and to the amplifier output to automatically attenuate the output of the amplifier during the transient increases.

Claim 22

A radio frequency transmitter, comprising: a radio frequency amplifier having an input and an output; an envelope detector coupled to the amplifier output for detecting an amplitude envelope of radio frequency signals at the amplifier output including a series-connected PIN diode and first capacitance connected across the amplifier output; a transient control circuit coupled to the envelope detector for automatically generating a control signal during transient increases in the amplitude envelope; and a controllable radio frequency attenuator coupled to the control signal and to the amplifier output to automatically attenuate the output of the amplifier during the transient increases.