Determination of a differential offset in a radio device and radio device
View Patent ↗A device for determining an offset value for an offset occurring in a differential transmission signal section of a radio device utilizes, for the purpose of determining the offset value, a signal processing section in a reception part of the radio device. A connecting device is further provided for interchangeably connecting outputs of the differential transmission signal section to inputs of the differential reception signal section.
1. A method for determining an offset value for an offset occurring in a differential transmission signal section of a radio device, which comprises the steps of:
inputting a test value into an input of the differential transmission signal section, resulting in a first signal being output at a first output of the differential transmission signal section and a second signal being output at a second output of the differential transmission signal section;
coupling the first signal into a first input and the second signal into a second input of a differential reception signal section of the radio device;
determining a first value of a reception signal output at an output of the differential reception signal section;
coupling the first signal into the second input and the second signal into the first input of the differential reception signal section;
determining a second value of the reception signal; and
calculating the offset value using the first value, the second value, and the test value.
2. The method according to claim 1 , further comprising the step of compensating for the offset in the differential transmission signal section by the steps of:
storing the offset value for the differential transmission signal section; and
subtracting the offset value from signal values of a transmission signal.
3. The method according to claim 2 , which comprises carrying out an offset compensation each time the radio device is started up.
4. The method according to claim 2 , which comprises carrying out an offset compensation within a time domain multiple access time slot during a time duration without transmission and reception activity.
5. The method according to claim 1 , which comprises calculating offset values both for the differential transmission signal section of an in-phase branch and for the differential transmission signal section of a quadrature branch of the radio device.
6. A radio device, comprising:
a differential transmission signal section having a transmission signal input and two transmission signal outputs;
a differential reception signal section having two reception signal inputs and a reception signal output;
a first device for generating a digital test value and for inputting the test value into said transmission signal input of said differential transmission signal section;
a second device for interchangeably connecting said transmission signal outputs of said differential transmission signal section to said reception signal inputs of said differential reception signal section, said second device connected between said differential reception signal section and said differential transmission signal section; and
a calculation device connected to said differential reception signal section for calculating an offset value from at least two values output from said differential reception signal section and the test value.
7. The radio device according to claim 6 , further comprising:
a memory for storing the offset value for the differential transmission signal section, said memory connected to said calculation device; and
a correction element for correcting the transmission signal by the offset value, said correction element connected to said first device and to said memory.
8. The radio device according to claim 6 , wherein said differential transmission signal section contains a differential digital-to-analog converter for generating two differential analog signals.
9. The radio device according to claim 8 , wherein said differential transmission signal section furthermore has an output driver connected to said digital-to-analog converter and receives the two differential analog signals.
10. The radio device according to claim 7 , wherein said correction element is connected upstream of said transmission signal input of said differential transmission signal section.