2G, 2.5G RF loopback arrangement for mobile device self-testing

摘要

In a mobile communication device a loopback technique is used to enable the receive chain circuitry and digital baseband block to perform self tests on the transmit chain circuitry of the same mobile communication device for 2G and 2.5G operating Bands and channels. A transmit chain circuit is set to transmit a selected receive Band channel, which is attenuated via a loopback path within the mobile communication device's front end module and, in some embodiments, via a leakage signal path between adjacent or proximate LNA inputs of separate receive chain circuits.

主权项

1. A method of self testing a transmission chain in a mobile phone radio device, the method comprising:
producing, by an RF transmit circuit portion of the mobile phone radio device, a modulated baseband signal within a preselected channel within a preselected receive frequency band; amplifying the modulated baseband signal; providing the amplified modulated baseband signal to a first node of an antenna switch module; receiving a first attenuated signal on a second node of the antenna switch module via a first leakage signal path between the first node and the second node, the first node and the second node not being on a same electrical signal path, the first attenuated signal comprising an attenuated version of the amplified modulated baseband signal; filtering the first attenuated signal by a first bandpass filter adapted to pass the preselected receive frequency band, the first bandpass filter outputting a loopback signal, the loopback signal being a first bandpass filtered version of the first attenuated signal; receiving the loopback signal by a first Low Noise Amplifier (LNA) in a first RF receive circuit portion of the mobile phone radio device, the first LNA receives an attenuated loopback signal via a second leakage signal path that is between the first bandpass filter and the first LNA, the first LNA is not in a same receive signal oath as the first bandpass filter, the first LNA is adjacent to a second LNA wherein the second LNA is in a same direct receive signal path past the first bandpass filter, the first leakage signal path being in series with the second leakage signal path; producing, by the first RF receive circuit portion, a received digital representation of the baseband signal from the attenuated loopback signal; calculating by a Digital Base Band (DBB) block a transmit quantification measurement of the RF transmit circuit portion using the received digital representation of the baseband signal.