Medium Complexity PCB Design

I need a medium complexity (3-4 layers) PCB designed for signal processing. The design should be capable of accommodating surface-mount components.

Requirements:
- 3-4 layers PCB design
- Signal processing functionality
- Surface-mount component integration
- Gerber file generation

Ideal Skills:
- Experience with PCB design software (e.g., Altium, Eagle)
- Strong understanding of signal processing circuits
- Proficiency in layout for surface-mount components
- Attention to detail and accuracy

Please provide samples of previous work.