Method of measuring quality of a signal received by a receiver of a two-dimensional linear modulation data communication system

A method for use in a receiver of a two-dimensional linear modulation data communication system, said receiver being responsive to a received signal received through a transmission channel of said system for producing a phase controlled baseband signal and a reproduced data signal derived from said phase controlled baseband signal, said method comprising the steps of:

• measuring a quality measure of said received signal by using said phase controlled baseband signal and said reproduced data signal with said quality measure divided into portions related to a noise component, a carrier phase jitter component, and a carrier frequency offset component, each component being introduced into said received signal in said transmission channel;
• using said reproduced data signal in estimating a data signal component which is influenced by an intercode interference component introduced into said received signal in said transmission channel;
• subtracting said data signal component from said phase controlled baseband signal to produce a difference signal having a phase difference relative to said reproduced data signal;
• giving said phase difference to said difference signal to produce a phase adjusted signal;
• and
• calculating a mean square of an inphase component of said phase adjusted signal to provide that portion of said quality measure which is related to said noise component.

A method for use in a receiver of a two-dimensional linear modulation data communication system, said receiver being responsive to a received signal received through a transmission channel of said system for producing a phase controlled baseband signal and a reproduced data signal derived from said phase controlled baseband signal, said method comprising the steps of:

• measuring a quality measure of said received signal by using said phase controlled baseband signal and said reproduced data signal with said quality measure divided into portions related to a noise component, a carrier phase jitter component, and a carrier frequency offset component, each component being introduced into said received signal in said transmission channel;
• and
• wherein said receiver produces an integrated phase error signal for use in phase controlling said received signal to produce said phase controlled baseband signal;
• said method further comprising the step of:
• averaging said integrated phase error signal to produce an averaged signal representative of that portion of said quality measure which is related to said carrier frequency offset component.

A method for use in a receiver of a two-dimensional linear modulation data communication system, said receiver being responsive to a received signal received through a transmission channel of said system for producing a phase controlled baseband signal and a reproduced data signal derived from said phase controlled baseband signal, said method comprising the step of:

• measuring a quality measure of said received signal by using said phase controlled baseband signal and said reproduced data signal with said quality measure divided into portions related to a noise component, a carrier phase jitter component, and a carrier frequency offset component, each component being introduced into said received signal in said transmission channel;
• and
• wherein said receiver produces an integrated phase error signal for use in controlling said received signal to produce said phase controlled baseband signal;
• said method further comprising the steps of:
• averaging said integrated phase error signal to produce an averaged signal representative of that portion of said quality measure which is related to said carrier frequency offset component;
• subtracting said averaged signal from said integrated phase error signal to produce a difference signal representative of a phase error;
• calculating a means square of said phase error to produce a mean square signal;
• using said phase controlled baseband signal and said reproduced data signal in producing an adjustment signal representative of an amount of influence caused to said mean square signal by said noise component and by an intercode interference component which are introduced into said received signal in said transmission channel;
• and
• subtracting said adjustment signal from said mean square signal to provide that portion of said quality measure which is related to said carrier phase jitter component.