摘要:
In a superheterodyne receiver, energy can bypass a filter by magnetically coupling to a metallic radio frequency shield. This is especially a problem with small form factor devices in which the metallic radio frequency shield is positioned close to the filter. By using a ferrite-embedded element positioned between the filter and the RF shield, some of the undesired harmonics produced by the mixer can be dissipated into heat.
摘要:
A hand-held, PCMCIA cellular radio modem card is described which uses a non-standard power output level. The non-standard power output is defined as the maximum RF power attainable such that the current drawn by the power amplifier does not exceed 400 mA. This definition permits the use of the wireless modem inside hand-held computing devices without the use of an additional battery pack extension.
摘要:
A detachable battery pack is connected to a personal computer card modem at the same side as an antenna. An advantage of this system is that the detachable battery pack can be added and removed from the personal computer card without affecting the antenna connection to the personal computer card. The antenna need not be connected to the personal computer card through the battery pack.