Abstract: Improved gain control for a digital signal processing (DSP) repeater, such as a bi-directional repeater, is disclosed. A repeater includes a back-end subsystem which comprises, for each channel in a set of wanted frequency channels that are amplified by the repeater, a coupler (314) arranged to provide a monitor signal corresponding with an output channel power level. A feedback loop (306) receives the monitoring signal, and incorporates a power control circuit (308) that compares the monitored output channel power level with a predetermined maximum output signal level (310). A corresponding control signal is generated, and provided to a variable attenuator (304) in order to maintain the individual output channel power level at or below the maximum output signal level (310). Advantageously, a DSP output level control function (404) is also provided, which maintains the output signal level of each digital channel below a maximum rated value for a digital-to -analogue converter (402).

Abstract: Improved gain control for a digital signal processing (DSP) repeater, such as a bi-directional repeater, is disclosed. A repeater includes a back-end subsystem which comprises, for each channel in a set of wanted frequency channels that are amplified by the repeater, a coupler (314) arranged to provide a monitor signal corresponding with an output channel power level. A feedback loop (306) receives the monitoring signal, and incorporates a power control circuit (308) that compares the monitored output channel power level with a predetermined maximum output signal level (310). A corresponding control signal is generated, and provided to a variable attenuator (304) in order to maintain the individual output channel power level at or below the maximum output signal level (310). Advantageously, a DSP output level control function (404) is also provided, which maintains the output signal level of each digital channel below a maximum rated value for a digital-to-analogue converter (402).

Abstract: Method and apparatus for detecting far end speech in a telephone apparatus. A speaker (14) produces far end sound from a far end signal, when received by the telephone apparatus. A microphone (12) generates a near end signal from near end sound, for transmission from the telephone apparatus. A hybrid (24) which passes the near and far end signals from an external two wire link (30) to and from the speaker and microphone, on respective first and second paths (1, 2) of a four wire link (28). Muting of the near end signal is effected when signal derived from the first path (1) of the four wire link (28) is detected as being representative of a condition of existence of far end signal.