8 Part A: Introduction © Tait Electronics Limited December 2007Power SavingThe TB8100 base station can save power by switching off parts of its circuitry.The standard base station has a limited ability to reduce the current that the basestation uses, but the Power Saving Modes license lets you configure threedifferent power saving modes. This gives greatly increased flexibility and makesit possible to get the power savings needed with a minimum sacrifice in qualityof service.Note: Power saving only occurs when the base station is battery-powered. It is not available if the PMU supplies more than one basestation.Power savingmodesA base station with a Power Saving Modes license can operate in Normal,Sleep, and Deep Sleep modes. These modes are enabled and configured in theService Kit.The base station begins in Normal mode. If the base station is idle (receives novalid signal) for a defined length of time, it switches to Sleep mode, which savesmore power. If the base station is idle for a further defined length of time, itswitches to Deep Sleep mode, saving even more power. When it receives avalid signal, it reverts to Normal mode.Both receiver and transmitter contribute to the power saving.The receiver is switched off, and then periodically switched back on. If itdetects a valid signal, it stays on, otherwise it is switched off again. The poweramplifier is always off when the base station is not transmitting. In power saving,other parts of the transmitter circuitry are switched off as well. The longer theTx keyup time you select, the more circuitry is switched off.Response times The more power saved, the longer the response time. Initially, the radio userneeds to press PTT and wait before speaking, to give enough time for thereceiver to come back on and for the transmitter to key up.Configuringpower savingYou configure power saving when you define the channel profile that the basestation will use. For each mode, you specify Rx cycling (how long the receiverstays switched off before it wakes up to check if there is a valid signal) and Txkeyup (how long it takes for the transmitter to key up). In addition, you specifyhow long the base station must be idle before it enters Sleep and Deep Sleepmodes. The exact amount of power saved varies, depending on the model ofbase station and the pattern of traffic.
