METHOD AND ARRANGEMENT RELATING TO TRANSCEIVERS

• US 20050164648A1
• Filed: 06/26/2001
• Published: 07/28/2005
• Est. Priority Date: 06/27/2000
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Gannholm, Magnus
• Granted Patent: US 6,952,564 B2
• Time in Patent Office: Days
• US Class Current: 455/84
• CPC Class Codes: H04B 17/14 of the whole transmission and reception path, e.g. self-test loop-back
• CPC Class Codes: H04B 17/19 Self-testing arrangements
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 17/29 Performance testing

Abstract

The invention relates to the field of methods and arrangements pertaining to transceivers. The object of the invention is to enable transceivers to be used more simply and more cheaply. This is achieved with an improved method of calibrating transceivers, and with transceivers that can be calibrated in accordance with the method. A sequence of signal connections (60-70) is established between a transmitter chain (3) and a receiver chain (5) in a transceiver. A corresponding sequence of signal paths is established from a baseband stage in the transmitter chain to a baseband stage in the receiver chain. Each signal path includes at least one specific component that shall be calibrated with the use of the established signal path, wherein any further components in said signal path will have already been calibrated with the use of earlier established signal paths. When calibrating the components, pre-determined test signals (TS1-TS11) are sent over the signal paths, wherein the response signals (RS1-RS11) are received as a response to the transmitted test signals. It is ascertained whether or not the components in the transceiver fulfil pre-determined performance requirements, on the basis of the test signals and the response signals. The components are adjusted when they do not fulfil performance requirements.

Claims

1. A method of calibrating components in a transceiver that comprises a transmitter chain and a receiver chain which include a pre-determined number of frequency stages and means for frequency transposition between said frequency stages, the method comprising:

successively establishing a sequence of signal connections between the frequency stages in the transmitter chain and the corresponding frequency stages in the receiver chain, thereby obtaining a sequence of signal paths from one baseband stage in the transmitter chain to a baseband stage in the receiver chain, wherein each signal path differs from the preceding signal paths by including one or more specific components that shall be calibrated and that are not included in any one of the preceding signal paths;

transmitting pre-determined test signals over each of said signal paths;

receiving response signals corresponding to the transmitted test signals;

establishing whether or not the performance or performances of the specific components for each signal path is/are acceptable in relation to the test signals and the response signals; and

adjusting the specific component or specific components so as to obtain an acceptable performance when it is established that said performance is unacceptable.

2. The method according to claim 1, wherein a digital interface is connected to the baseband stage of the transceiver, and wherein the method is commenced by mapping the signal influence of the digital interface.

3. The method according to claim 1, wherein the transceiver includes at least one filter which constitutes the specific component in one of said signal paths.

4. The method according to claim 3, wherein the test signal used in the calibration of the filter is a multi-frequency signal that has a predetermined frequency range.

5. The method according to claim 4, wherein the multi-frequency signal is a frequency sweep.

6. The method according to claim 4, wherein the multi-frequency signal includes solely one I-component or solely one Q-component.

7. The method according to claim 1, wherein the transceiver includes at least one first pair of sideband suppressing mixers which constitute the specific components in one of the signal paths, wherein the method includes setting at least one of the mixers so that the associated response signal will show undesired sidebands and wherein adjustment of said first pair of sideband suppressing mixers includes adjustment of said mixers so as to suppress undesired sidebands to a predetermined extent.

8. The method according to claim 7, wherein the test signal used in the calibration of said first pair of sideband suppressing mixers is a single frequency signal.

9. The method according to claim 1, wherein the transceiver includes at least one amplifier which constitutes the specific components in one of said signal paths, wherein the test signal used in the calibration of said amplifier includes at least two frequency components, wherein intermodulation products of the frequency components are identified on the basis of the corresponding response signal, and wherein adjustment of the amplifier includes adjustment of the linearity of the amplifier, so that the identified intermodulation products will lie below pre-determined limit values.

10. The method according to claim 9, wherein the linearity of the amplifier is adjusted by controlling the supply of current to the amplifier.

11. The method according to claim 9, wherein the linearity of the amplifier is adjusted by controlling an input impedance of the amplifier.

12. A transceiver circuit comprising:

a transmitter chain and a receiver chain that include a pre-determined number of frequency stages and means for frequency transposition between the frequency stages and;

means for establishing successively a sequence of signal connections between the frequency stages in the transmitter chain and the corresponding frequency stages in the receiver chain, thereby obtaining a sequence of signal paths from a baseband stage in the transmitter chain to a baseband stage in the receiver chain, wherein each signal path differs from the preceding paths by virtue of including one or more specific components that are not included in any one of the preceding signal paths.

13. The transceiver circuit according to claim 12, further comprising:

means for transmitting pre-determined test signals over each of said signal paths;

means for receiving response signals corresponding to the transmitted test signals;

means for establishing whether or not the performance of the component or components specific to each signal path is acceptable or not on the basis of the test signals and the response signals; and

means for adjusting the specific component or components so as to obtain acceptable performance when it is established that component performance is not acceptable.