Telecommunications receiver employing CMOS logic - has NAND=gates controlling AGC and detector and amplifier circuit including FET volume control

摘要

The radio receiver uses C-MOS logic as a periodic amplifiers in place of bipolar transistors. The receiver operates for example in the frequency range 145 to 255 KHz with a ferrite aerial coupled to one of two inputs of a NAND gate, the other input of which is used for automatic gain control. The output of the NAND gate is coupled to two further NAND gates one of which controls the automatic gain control and the other of which is coupled to a detector and amplifier circuit including an FET volume control. The resulting circuit avoids the use of tuned coils and improves reliability, and simplifies circuitry without reduction in the quality of sound reproduction.