Radio channel squelching systems
AssigneeTelefonaktiebolaget LM Ericsson
InventorsJafar Rostamy, Johan von Perner, Anders Engman
Life of this patent
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Abstract
Detection of in-band noise in a radio communications voice channel is provided by mixing a signal having a known frequency into a radio signal containing a voice channel signal in an in-band range, thereby translating the voice channel signal out of the in-band range. The in-band range is thereafter examined for the presence of noise signal energy whose presence can be indicative of in-band noise. Squelching of the voice channel is provided in the event that in-band noise energy exceeds a predetermined threshold.
Claims13
An apparatus for squelching a radio signal having an in-band frequency range, the apparatus comprising:
- means for receiving the radio signal;
- means for mixing a first signal having a known frequency with the radio signal to produce a second signal, the known frequency being selected so that signals from the in-band frequency range are translated out of the in-band frequency range;
- means for determining if a parameter in said in-band frequency range exceeds a first predetermined threshold;
- and
- means for receiving the radio signal and selectively squelching the radio signal based upon an output of said determining means.
A method for squelching a radio signal having an in-band frequency range, the method comprising the steps of:
- receiving the radio signal;
- mixing a first signal having a known frequency with the radio signal to obtain a second signal, the known frequency being selected so that signals from the in-band frequency range are translated out of the in-band frequency range;
- measuring an amount of noise energy found in the in-band frequency range;
- comparing the amount of noise energy measured to a predetermined threshold;
- and
- squelching the radio signal if the measured noise energy is greater than or equal to the predetermined threshold.
A method for squelching a radio communications channel, the method comprising the steps of:
- receiving a radio signal;
- mixing a first signal with the radio signal to obtain a second signal;
- determining an amount of noise in a bandwidth below a desired, information bearing portion of the second signal;
- comparing the amount of noise determined to a predetermined threshold;
- and
- squelching the radio communications channel if the amount of noise determined is greater than or equal to the predetermined threshold.
A base station comprising:
- a receiver for receiving a radio signal;
- a tone generator for providing a tone signal at a SAT frequency of said base station;
- a mixer for multiplying the radio signal with the tone signal to produce a mixed signal wherein a voice channel within said radio signal is translated to a higher frequency;
- a noise measurement device for measuring noise present in a bandwidth below said higher frequency;
- and
- a squelching determination device for squelching the radio channel if the noise present in said bandwidth exceeds a predetermined threshold.
Dependencies are inferred from the claim text.