Communications: radio wave antennas – Antennas – Measuring signal energy
Reexamination Certificate
2000-06-27
2001-11-06
Wimer, Michael C. (Department: 2821)
Communications: radio wave antennas
Antennas
Measuring signal energy
Reexamination Certificate
active
06313799
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a diagnostic device for a multi-antenna arrangement with a diversity processor.
2. The Prior Art
When testing active and passive components of a mobile receiver installation, for example a radio receiver, multi-antenna arrangements with antenna diversity are problematic due to differentiated testing of the individual antenna and the condition of the antenna's electrical connections to the radio receiver. In addition, the interfaces available for the tie-up for measuring and testing systems are difficult to access and require extensive dismantling work. It is difficult to determine which antenna is connected at the given time, due to the switching position of the antenna diversities. Antenna determination can not be achieved by measurements of the receiving level on the antenna connection box of the radio receiver because the signal level falls short of a defined preset value in diversity systems. Therefore, the radio receiver is automatically switched via a change-over switch to one of the other antennas where an adequate reception level can be detected.
A circuit arrangement for testing the function of mobile radio reception installations is known from European Patent EP 0 806 849 A2, which can be used with diversity systems as well. This invention discloses a high-frequency signal that is generated by the circuit on the output side. The HF-signal substantially corresponds with the adjusted receiver frequency of the radio receiver and is coupled in via the receiver antenna, whereby the level of the received signal is measured. A switching signal generator is used to sequentially step the antenna switch of a diversity processor. This allows the high-frequency signal to be coupled in by different antennas of the diversity system, and the received power of the individual antenna can be measured. However, this system does not provide a defined starting condition for beginning the function test.
Another circuit arrangement for testing multi-antenna systems is described in German Patent DE 195 13 872 A1. This invention describes an antenna-specific pulse sequence, which is generated either indirectly by the radio receiver, an external testing device, or a special converter circuit, and the change-over switch of the antenna diversity system is switched through to the radio receiver according to the pulse sequence. The pulse sequence can be fed into the diversity system either by the antenna cable or an intermediate frequency output of the radio receiver. The intermediate arrangement of filters separates the test pulses from the main signals transmitted by the lines. A test signal is subsequently transmitted on the same channel, and the receiver conditions of the individual antenna can then be tested by the test signal.
It is essential to this system to intervene with or make changes on the circuitry that relate to the diversity system and/or the radio receiver. Consequently, these systems are not suitable for testing existing radio receiver installations with antenna diversity systems.
SUMMARY OF THE INVENTION
An object of the invention is to create a diagnostic device for multi-antenna systems that provides differentiated testing of the individual antennas of a multi-antenna system without intervening with the circuitry in the receiver installation. This is accomplished by testing two interfaces of the antenna system, namely the intermediate-frequency (IF) input of the diversity processor, and the HF-output of the antenna installation. The two interfaces serve to connect a test unit as well as a control unit, which are external units that can be employed within the framework of the controls at the end of an assembly line, or in auto repair shops. Consequently, this device requires no intervention with the circuitry of passive or active functional elements of the antenna system or the radio receiver. In particular, these systems may be conventional diversity systems whose control signal in the diversity mode consists of an IF-signal, with FM-reception a 10.7 MHz signal, on which a dc voltage component is applied.
The test unit comprises, a transmitting and receiving module and serves to build up an HF-circuit into which the multi-antenna system to be tested is tied. Provision is made for a transmitting antenna for sending the test signal generated by the test unit. The test signal is then fed into the switched-through antenna of the multi-antenna system, and then supplied again to the test unit through the antenna for analysis. The test unit is actively connected to a control unit comprising a signal generator, a dc voltage source and an interference simulator. The control unit supplies the control signal required for the diversity processor, as well as simulating conditions of interference in a defined way. These conditions of interference are defined, depending on the properties and adjustments of the diversity processor, wherein the stepping of the diversity processor to the next antenna is prompted in response to a defined interference. Therefore, the diagnostic device is intended to prompt controlled stepping of the diversity processor according to conditions of interference that are generated by the control unit. The signal received from the test unit reflects the condition of the switched-through antenna, including its lines of connection. It is particularly important to allocate the measurements to individual antennas, so that the function test starts in a reset mode of the diversity processor. This reset mode is first switched through to a defined known antenna, which is the main antenna. Following the tie-up of the control unit, the diversity mode is activated with the gradual application of a dc voltage on the IF control signal, without changing the antenna. A test process that has to be wound off by the interference simulator, in coordination with the test unit, can now be initiated at a particular point in time.
In another example, the control signal is an intermediate-frequency signal, i.e. with FM-reception having a 10.7 MHz signal.
The test signal, which is generated by the test unit, may be similar to the IF-signal. The test unit can log the antenna-specific measuring signals if needed, for comparison to standard values. The measuring signals are represented in a suitable manner, so that the electrical connection lines of individual antennas can be checked, with the help of the record of measurements.
It is advantageous that the control unit and the test unit form one single structural unit. This single unit may be integrated in other test devices as well.
Since the antenna amplifier and the diversity processor frequently form one structural unit, the diagnostic device is tied to the IF-input as well as to the HF-output of a structural unit.
Furthermore, it is essential that only those conditions of interference, which are simulated by the interference simulator, are active over time spans that are shorter than the dwelling time over which an individual antenna fails. This is an important precondition for stepping to the next successive antenna to take place, allowing for a differentiated measuring of each antenna.
REFERENCES:
patent: 5864319 (1999-01-01), Paulus
patent: 195 13 872 (1996-10-01), None
patent: 299 11 085 (1999-10-01), None
patent: 0 806 849 (1997-04-01), None
Thimm Peter
Wagner Martin
Collard & Roe P.C.
FUBA Automotive GmbH & Co. KG
Wimer Michael C.
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