Method for receiving digital radio signals and a digital radio signals receiver

A digital radio signal receiver for receiving digital radio signals at a predetermined transmission rate, comprising:

• a digital demodulation means for demodulating said digital radio signals;
• a bit error ratio monitoring means for monitoring a bit error ratio in the digital demodulation means;
• and
• a sampling rate changing means for changing a sampling rate at which said digital radio signals at said predetermined transmission rate are sampled for digital demodulation to a higher level when the bit error ratio exceeds a specified upper limit and to a lower level when the bit error ratio falls below a specified lower limit based on a signal from the bit error ratio monitoring means.

A digital radio signal receiver, comprising:

• a digital demodulation means for demodulating a digital radio signal;
• a bit error ratio monitoring means for monitoring a bit error ratio in the digital demodulation means;
• a sampling rate changing means for changing a sampling rate of the digital demodulation means to a higher level when the bit error ratio exceeds a specified upper limit and to a lower level when the bit error ratio falls below a specified lower limit based on a signal from the bit error ratio monitoring means;
• and
• a digital modulation system of the digital demodulation means being one of .pi./4-shift differential quadrilateral phase shift keying and differential quadrilateral phase shift keying, the digital demodulation means being a differential detector having shift registers, and the sampling rate changing means changing a frequency of a sampling clock and changing a number of bits of each of said shift registers in the differential detector to adapt to the frequency of the sampling clock.

A digital radio signal receiver for receiving digital radio signals at a predetermined transmission rate, comprising:

• a differential detector for demodulating said digital radio signals in said digital radio signal receiver;
• a bit error ratio monitor for detecting an error information of digital demodulation and calculating a bit error ratio on the basis of said error information;
• a sampling rate changing module for changing a sampling rate at which said digital radio signals at said predetermined transmission rate are sampled in said differential detector for digital demodulation based on a signal from said bit error ratio monitor, said sampling rate being shifted to a higher frequency than a present frequency when said bit error ratio goes beyond a specified upper limit and to lower frequency when the bit error ratio falls below a specified lower limit;
• and
• a sampling clock selector for supplying sampling clock signals determined by said sampling rate changing module to said differential detector.

A digital radio signal receiver for receiving digital radio signals at a predetermined transmission rate, comprising:

• a differential detector for demodulating said digital radio signals in said digital radio signal receiver to produce a demodulated digital signal;
• a bit error ratio monitor for detecting errors in the demodulated digital signal and calculating a bit error ratio;
• a sampling rate changing module for changing a sampling rate at which said digital radio signals at said predetermined transmission rate are sampled in said differential detector for digital demodulation based on a signal from said bit error ratio monitor, said sampling rate being shifted to a higher frequency than a present frequency when said bit error ratio goes beyond a specified upper limit and to a lower frequency when the bit error ratio falls below a specified lower limit;
• a sampling clock selector for supplying sampling clock signals determined by said sampling rate changing module to said differential detector;
• and
• said upper limit of said bit error ratio being 10.sup.-2 and said lower limit of said bit error ratio being 10.sup.-3.

A digital radio signal receiver comprising:

• a differential detector for demodulating a digital signal in said digital radio signal receiver;
• a bit error ratio monitor for monitoring an error information signal, detecting errors in the demodulated digital signal, and calculating a bit error ratio;
• a sampling rate changing module for changing a sampling rate for digital demodulation of said digital signal at a given transmission rate based on a signal from said bit error ratio monitor, said sampling rate for digital demodulation being shifted to a higher frequency than a present frequency when said bit error ratio goes beyond a specified upper limit and to a lower frequency when the bit error ratio falls below a specified lower limit;
• a sampling clock selector for supplying sampling clock signals determined by said sampling rate for digital demodulation changing module to said differential detector;
• and
• a framing portion and voice detector for generating said error information for digital demodulation.

A digital radio signal receiver comprising:

• a differential detector for demodulating a digital signal in said digital radio signal receiver;
• a bit error ratio monitor for monitoring an error information signal, detecting errors in the demodulated digital signal, and calculating a bit error ratio;
• a sampling rate changing module for changing a sampling rate for digital demodulation of said digital signal at a given transmission rate based on a signal from said bit error ratio monitor, said sampling rate for digital demodulation being shifted to a higher frequency than a present frequency when said bit error ratio goes beyond a specified upper limit and to a lower frequency when the bit error ratio falls below a specified lower limit;
• a sampling clock selector for supplying sampling clock signals determined by said sampling rate for digital demodulation changing module to said differential detector;
• a framing portion and voice detector for generating said error information for digital demodulation;
• and
• said error ratio monitor receiving and detecting said error information from said framing portion and voice detector.

A method for receiving digital radio signals comprising the steps of:

• detecting an error information for digital demodulation;
• calculating a bit error ratio from said error information;
• producing a sampling rate for digital demodulation of said digital radio signal at a given transmission rate based on said bit error ratio;
• changing said sampling rate for digital demodulation into a higher frequency when said bit error ratio goes beyond a specified upper limit and to a lower frequency when the bit error ratio falls below a specified lower limit;
• and
• supplying a sampling clock signal determined by said sampling rate for digital demodulation.