Quasi iso-gain supply voltage function for envelope tracking systems
View Patent ↗A method of defining a quasi iso-gain supply voltage function for an envelope tracking system is disclosed. The method includes a step of capturing iso-gain supply voltage values versus power values for a device under test (DUT). Other steps involve locating a minimum iso-gain supply voltage value, and then replacing the iso-gain supply voltage values with the minimum iso-gain supply voltage value for corresponding output power values that are less than an output power value corresponding to the minimum iso-gain supply voltage value. The method further includes a step of generating a look-up table (LUT) of iso-gain supply voltage values as a function of input power for the DUT after the step of replacing the iso-gain supply voltage values with the minimum iso-gain supply voltage value for corresponding output power values that are less than an output power value corresponding to the minimum iso-gain supply voltage value.
1. A method of defining a quasi iso-gain supply voltage function for an envelope tracking system comprising:
capturing into a memory array iso-gain supply voltage values versus output power values and input power values over a predetermined input power range for a device under test (DUT);
locating a minimum iso-gain supply voltage value within the memory array;
replacing the iso-gain supply voltage values within the memory array with the minimum iso-gain supply voltage value for corresponding output power values that are less than an output power value corresponding to the minimum iso-gain supply voltage value;
generating a look-up table (LUT) of iso-gain supply voltage values as a function of input power values from the iso-gain supply voltage values and input power values captured in the memory array; and
writing the LUT to a tangible computer-readable medium.
2. The method of claim 1 wherein the DUT is a power amplifier configured to operate in the envelope tracking system.
3. The method of claim 2 wherein the predetermined input power range is a predetermined supply voltage operating range of the envelope tracking system.
4. The method of claim 2 wherein quasi iso-gain supply voltage tracks instantaneous output power minimums for a gain target that is higher than a small signal gain of the power amplifier.
5. The method of claim 1 wherein a degradation of adjacent channel leakage ratio (ACLR) is less than 0.1 dB for an envelope tracking transmit system employing the quasi iso-gain supply voltage function versus the envelope tracking system without employing the quasi iso-gain supply voltage function.
6. The method of claim 1 wherein a degradation of error vector magnitude (EVM) is less than 0.01% for an envelope tracking transmit system employing the quasi iso-gain supply voltage function versus the envelope tracking system without employing the quasi iso-gain supply voltage function.
7. An automated test system (ATS) of defining a quasi iso-gain supply voltage function for an envelope tracking system comprising:
a system controller programmed to execute steps comprising:
capturing into a memory array iso-gain supply voltage values versus output power values and input power values over a predetermined input power range for a device under test (DUT);
locating a minimum iso-gain supply voltage value within the memory array;
replacing the iso-gain supply voltage values within the memory array with the minimum iso-gain supply voltage value for corresponding output power values that are less than an output power value corresponding to the minimum iso-gain supply voltage value;
generating a look-up table (LUT) of iso-gain supply voltage values as a function of input power values from the iso-gain supply voltage values and input power values captured in the memory array; and
writing the LUT to a tangible computer-readable medium.
8. The ATS of claim 7 wherein the DUT is a power amplifier configured to operate in the envelope tracking system.
9. The ATS of claim 8 wherein the predetermined input power range is a predetermined supply voltage operating range of the envelope tracking system.
10. The ATS of claim 8 wherein quasi iso-gain supply voltage tracks instantaneous output power minimums for a gain target that is higher than a small signal gain of the power amplifier.
11. The ATS of claim 7 wherein a degradation of adjacent channel leakage ratio (ACLR) is less than 0.1 dB for an envelope tracking transmit system employing the quasi iso-gain supply voltage function versus the envelope tracking system without employing the quasi iso-gain supply voltage function.
12. The ATS of claim 7 wherein a degradation of error vector magnitude (EVM) is less than 0.01% for an envelope tracking transmit system employing the quasi iso-gain supply voltage function versus the envelope tracking system without employing the quasi iso-gain supply voltage function.
13. A tangible computer-readable medium having computer instructions stored thereon, wherein the computer instructions are readable by a computing device of an automated test system (ATS) to perform operations for defining a quasi iso-gain supply voltage function for an envelope tracking system, the operations comprising:
capturing into a memory array iso-gain supply voltage values versus output power values and input power values over a predetermined input power range for a device under test (DUT);
locating a minimum iso-gain supply voltage value within the memory array within the predetermined input power range;
replacing the iso-gain supply voltage values within the memory array with the minimum iso-gain supply voltage value for corresponding output power values that are less than an output power value corresponding to the minimum iso-gain supply voltage value;
generating a look-up table (LUT) of iso-gain supply voltage values as a function of input power values from the iso-gain supply voltage values and input power values captured in the memory array; and
writing the LUT to a tangible computer-readable medium.
14. The tangible computer-readable medium of claim 13 wherein the DUT is a power amplifier configured to operate in the envelope tracking system.
15. The tangible computer-readable medium of claim 14 wherein the predetermined input power range is a predetermined supply voltage operating range of the envelope tracking system.
16. The tangible computer-readable medium of claim 13 further comprising generating a look-up table (LUT) of iso-gain supply voltage values as a function of input power for the DUT after replacing the iso-gain supply voltage values with the minimum iso-gain supply voltage value for the corresponding output power values that are less than an output power value corresponding to the minimum iso-gain supply voltage value.
17. The tangible computer-readable medium of claim 14 wherein quasi iso-gain supply voltage tracks instantaneous output power minimums for a gain target that is higher than a small signal gain of the power amplifier.
18. The tangible computer-readable medium of claim 13 wherein a degradation of adjacent channel leakage ratio (ACLR) is less than 0.1 dB for an envelope tracking transmit system employing the quasi iso-gain supply voltage function versus the envelope tracking system without employing the quasi iso-gain supply voltage function.
19. The tangible computer-readable medium of claim 13 wherein a degradation of error vector magnitude (EVM) is less than 0.01% for an envelope tracking transmit system employing the quasi iso-gain supply voltage function versus the envelope tracking system without employing the quasi iso-gain supply voltage function.