Method and apparatus for layered modulation

A signal simulator for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising:

• a first modulator for modulating a bit stream of the upper layer to produce an upper layer signal;
• a noise generator for adding noise to the upper layer signal;
• a second modulator for modulating a bit stream of the lower layer to produce a lower layer signal;
• an attenuator for attenuating the lower layer signal;
• and
• a combiner for combining the noise-added upper layer signal and the attenuated lower layer signal to produce a composite layer modulated signal.

A receiver system for simulating a layer modulated signal, comprising:

• a first antenna for receiving an upper layer signal from a first satellite transponder;
• a first amplifier for amplifying the received upper layer signal;
• a second antenna for receiving a lower layer signal from a second satellite transponder;
• a second amplifier for amplifying the received lower layer signal;
• an attenuator for attenuating the received lower layer signal;
• and
• a combiner for combining the upper layer signal and the attenuated lower layer signal to produce a composite layer modulated signal.

A method for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising the steps of:

• providing an upper layer signal comprising a first modulated bit stream;
• providing a lower layer signal comprising a second modulated bit stream;
• attenuating the lower layer signal;
• and
• combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal;
• tuning the composite layer modulated signal;
• evaluating the composite layer modulated signal performance based upon the in-phase and quadrature components of the layer modulated signal.

A signal simulator for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising:

• a first modulator for modulating a bit stream of the upper layer to produce an upper layer signal;
• a noise generator for adding noise to the upper layer signal;
• a second modulator for modulating a bit stream of a lower layer to produce a lower layer signal;
• an attenuator for attenuating the lower layer signal;
• a combiner for combining the noise-added upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal;
• and
• a directional coupler, for tapping the composite layer modulated signal.

A signal simulator for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising:

• a first antenna for receiving the upper layer signal from a first satellite transponder;
• a first amplifier for amplifying the received upper layer signal;
• a second antenna for receiving the lower layer signal from a second satellite transponder;
• a second amplifier for amplifying the received lower layer signal;
• an attenuator for attenuating the received lower layer signal;
• and
• a combiner for combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal.