As evident in Figures 3 and 4, the application of digital predistortion yields a greater than 10 dB improvement in the adjacent channel power ratio
. Data was also collected for a two-carrier stimulus utilizing the same experimental conditions, signals and evaluation board.
Dedicated one-button measurements, including channel power, adjacent channel power ratio
, and occupied bandwidth, confirm the distortion level or channel power performance of an AMPS, TDMA, CDMA, or GSM transmitter.
However, the adjacent channel power ratio
(ACPR) of the Doherty amplifier is somewhat lower than for the reference design.
The filtering capability of the ISL5416 provides >100 dB of out-of-band filtering to address even the most aggressive 3G ACPR (Adjacent Channel Power Ratio
Next comes measuring the spurious emissions from the DUT, which requires looking at leakage into adjacent channels, such as adjacent channel power ratio
Very good adjacent channel efficiency is obtained at -50 dBc adjacent channel power ratio
(ACPR), as shown in Figure 9.
The SE2522BL is capable of +23 dBm of linear output power at an adjacent channel power ratio
(ACPR) of -30 dBc.
These measurements include field strength, channel power, occupied bandwidth, adjacent channel power ratio
, carrier to interference ratio and interference analysis.
Root raised cosine (RRC) filtering is added to the adjacent channel power ratio
(ACPR) measurement window to meet the needs of engineers performing 3G WCDMA FDD conformance testing.
(2) Both are tested with a two-carrier WCDMA signal, and in both cases the amplifier needs to meet an IMD requirement of -37 dBc and an adjacent channel power ratio
(ACPR) of -40 dBc.
In the 802.11b mode, the SE2525L meets all adjacent channel power ratio
requirements at +23 dBm output power.