Develop a functional design for a variable frequency and amplitude signal processor. This processor should decompose an input signal into specified frequency bands, apply custom amplification to each frequency band, and recombine the signals. The design can employ either analog or digital processing. Clearly identify the design levels, functional requirements, and operations of the different levels in the architecture.

The system must:

Accept an input signal source with a source resistance of $1000$ and a maximum input voltage of $2$ V peak$-$to$-$peak.

Allow for adjustable amplitude for each frequency band.

Be powered by a standard $240V,50Hz$ AC outlet.

Deliver a maximum of $50$ W to an $8$ speaker.

Decompose the signal into four distinct frequency bands: $50Hz,300Hz,1kHz,$ and $10$ kHz$.$

Restrict your architecture to levels $0$ and $1$ only. For level $1,$ provide the functional requirements and operation of the following modules:

Bandpass Filters for the specified frequency bands.

Frequency Band Amplifiers with adjustable gain control for each frequency band.

Signal Summation to combine all processed frequency bands.

High Gain Amplifier to drive the final output.

Power Output Stage to supply the required current.