Patent ID: 6667669
Filing Date: 2003-12-23
Classification: H03G,H03H

Abstract:
A differential diode attenuator circuit for selectively attenuating a differential analog signal having a first part and a second part that are 180Â° out of phase with each other, said attenuator circuit comprising:a first differential input line responsive to the first part of the differential analog signal; a second differential input line responsive to the second part of the differential analog signal; a first non-attenuation line coupled to the first input line, said first non-attenuation line including a first pass-through diode; a first attenuation line coupled to the first input line, said first attenuation line including a first attenuation resistive element; a second non-attenuation line coupled to the second input line, said second non-attenuation line including a second pass-through diode; a second attenuation line coupled to the second input line, said second attenuation line including a second attenuation resistive element; a first differential output line coupled to the first non-attenuation line and the first attenuation line; a second differential output line coupled to the second non-attenuation line and the second attenuation line; and a first control line coupled to the circuit at a location where the first part of the differential signal and the second part of the differential signal substantially cancel each other, said first control line being responsive to a DC bias signal that biases the first and second pass-through diodes to cause the differential signal to pass through the first and second non-attenuation lines to the first and second output lines substantially unattenuated.