Here is an example of the design and realisation of RF preamplifiers for frequencies up to 30 MHz. These are amplifiers with high dynamic range and low noise figure. The preamplifier is designed as a stand-alone module connected via SMA RF connectors and a 6-pin connector with power supply and output from a temperature sensor. The module consists of a PCB and a heat sink. A temperature sensor is placed between them to control the fan speed. The preamplifiers are of push-pull design.
Double preamp
- common emiter design
- push-pull
- high dynamic range
- gain 20 dB
- low noise, high power transistor
- internal LPF (30 MHz)
- internal DC/DC converter
- fan with temp control
- modular
- rack mount enclosure
This box contains two preamplifier modules, a 30MHz Low Pass Filter and a DC/DC converter for 24V DC power supply. The preamps are both a common emitter and a push-pull. Modular wiring allows easy replacement - for example with another module (design).
Norton preamp
- Norton design
- push-pull
- high dynamic range
- gain 12 dB
- low noise, high power transistor
- internal DC/DC converter
- fan with temp control
- modular (3 preamps)
- rack mount enclosure
This preamp box contains three Norton design and push-pull modules. The modular design allows for easy service or replacement with another design. Modules include sensors for fan speed control. The entire box is powered by 24 VDC and includes an internal DC/DC redundant power supply with multiple stages of EMI/RFI filters.
Module of preamp
- different designs
- push-pull
- high dynamic range
- low noise, high power transistor
- SMA RF connectors
- temp sensor
- heatsink
Example of a modular preamplifier. This can be designed as a common emitter or base circuit. The push-pull circuit achieves better dynamics. Using trimmers, the bias current or balance can be adjusted. The whole module can be used separately or installed in another enclosure. The module also has its own temperature sensor lead to a common 6-pin connector. This is also used to power the module.
