VLF RECEIVER JFET OP AMP GENERATOR

First, it had to retain the 50-fl input and output impedances that are standard in RF systems. Several requirements were developed for the RF amplifier.

VLF RECEIVER JFET OP AMP GENERATOR

In addition to the receiver, I wanted to boost my signal generator 50-fl output to make it easier to develop some AM and VLF projects that I am working on and to provide a preamplifier for a square-loop antenna that tunes the AM BCB, Although most listening on the AM BCB is to powerful local stations (where receivers with no RF amplifier and a loop-stick antenna will work nicely), those who are interested in DXing are not well served. Many otherwise fine communications or entertainment-grade 'general coverage' receivers operate from 100 kHz to 30 MHz or so, and that range initially sounds really good to the VLF through AM BCB DXer, But when examined closer, it turns out that the receiver lacks sensitivity on the bands below either 2 or 3 MHz, so it fails somewhat in the lower end of the speci mm. The original need for this amplifier was that 1 needed an amplifier to boost AM BCB DX signals. Many designs offer -3 dB frequency response limits of 3 to 30 MHz, or 1 to 30 MHz, but rarely are t he VLF, LF, or even the entire AM broadcast, band (540 to 1700 kHz) covered.

A number of different, circuits published, including some by me, but one failing that I've noted on most of them is that they often lack response at the low end of the frequency range. Typical applications include boosting the output of RF signal generators (which tend to be normally quite low level), antenna preamphfication, loop antenna amplifier, and in the front ends of receivers. In many situations, a broadband (as opposed to tuned) RF amplifier is needed.

Vlf receiver jfet op amp