The Problems We are Trying to Solve

• Intermodulation – multiple signals mixing and producing unwanted products – produced by all active components

• Passband ripple – signal level variation across the normal receiver passband – a common problem with crystal filters

• Group Delay – different frequencies pass through a filter at different speeds causing unwanted phase shifts – can be a problem with some digital modes

• Phase Noise – modulates every signal with the noise spectrum of the local oscillator – makes the close-in noise floor higher