160m to 6m high perfomance receiver project . Back End Subsystem
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The Back End subsystem is the second part of the high performance 160m-6m HF receiver project. It comprises:

IF Selectivity Board box unit
IF Crystal Filters

IF Variable Gain Board box unit
Signal Path
Control Path
Closing the Loop
Set-point Reference

IF Detector Board box unit
Noise Filters
Quadrature Sampling Detector

Audio amplifier box unit

Power Supply
Rectifier board module
Switcher board box

Overall Control Logic




Due the complexity involve in the construction of the units I started with easiest one, the Power Supply.
It includes the rectifier board and the switcher box module.

The Rectifier Board


The rectifier board contains the mains toroidal transformer, rectifier and filtering providing the unregulated +24V raw DC voltage to the Switcher module.

Due the high prices of the transformer and top quality aluminium electrolytic capacitors I decided to use instead a cheaper commercial laboratory grade power supply. Later I will decide whether to include it


Rectifier board documentation


  The Switcher module box  



The Switcher module box provides a preregulated set of voltages needed to power different sections of the HF receiver.
On each section of the receiver lover voltages are derived by means of on board Low-Drop Out voltage regulators.
Supply voltages provided by the switcher are:
+14V/5Amp. Used to power +12V on board LDO regulators and the audio section.
-14V/2Amp. Used to power -12V on board LDO regulators.
+18V/1Amp. Used to power the +15V on board regulator.
+5V/5Amp. Used to directly power the digital circuitry.
Switcher features are:
Four main supply voltages with good regulation and minimal ripple from a single 24V DC source.
Efficient pre-regulation of the four main supply voltages.
Over current protection of the four main supply voltages.
Over voltage protection of the four main supply voltages.
Digital LCD voltmeters supervising voltages on input and output ports.
Under voltage protection.
Simple pushbutton like On/Off control.
Handshaking with the main on board Microcontroller.

Switcher doc

Switcher module documentation


Power Supply diagram

Power Supply switcher diagram
(click to enlarge)



Next: The Audio section (coming soon)

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