GB2370458A

GB2370458A - Testing an electronic communications device

Info

Publication number: GB2370458A
Application number: GB0031329A
Authority: GB
Inventors: Betty Brand
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2000-12-21
Filing date: 2000-12-21
Publication date: 2002-06-26
Also published as: GB0031329D0

Abstract

An electronic communications device such as a mobile phone handset 1 operating in a first frequency band is tested using a test set 2 operating in a second frequency band. The test signal output from the test set is converted to the frequency band of the mobile phone before being applied to the mobile phone. A signal from the mobile phone is converted to the frequency band of the test set before being applied to the test set. Thus a CDMA handset operating at 466.05MHz can be tested using a PCS test set operating at 1470.05MHz.

Description

SYSTEM AND METHOD FOR TESTING AN ELECTRONIC COMMUNICATIONS DEVICE The present invention relates to a method and system for testing an electronic communications device.

Background of the Invention When testing an electronic communications device such as a mobile telephone, it is necessary to employ testing equipment which operates in the same frequency band as that in which the device to be tested operates.

Accordingly, a different testing equipment is required for each device to be tested operating in a different frequency band. For example, if a CDMA mobile telephone which operates in the 450 MHz band is to be tested, then testing equipment which operates in that band is required. If a PCS (Personal Communications Service) device is to be tested, then different testing equipment operating in the PCS frequency band (1900 MHz) is required.

This is clearly inconvenient and costly.

The present invention aims to address the above problems.

Summary of the Invention According to one aspect of the present invention, there is provided a method for testing an electronic communications device operable in a first frequency band, the method comprising: generating a first test signal in a

second frequency band different from said first frequency band ; converting said first test signal into a second test signal in said first frequency band ; and supplying said second test signal to said electronic communications equipment.

According to another aspect of the present invention, there is provided a method for testing an electronic communications device operable in a first frequency band using a testing device operable in a second frequency band, the method comprising: generating an output signal in said first frequency band using said electronic communication device; converting said output signal into a test signal in said second frequency band; and supplying said test signal to said testing device.

According to another aspect of the present invention, there is provided a system for testing an electronic communications device operable in a first frequency band, the system comprising: a first signal source for providing a first test signal in a second frequency band different from said first frequency band; a converter for converting said first test signal into a second test signal in said first frequency band; and means for supplying said second test signal to said electronic communications device.

According to another aspect of the present invention, there is provided a system for testing an electronic communications device operable in a first frequency band, the system comprising: a testing device for receiving a test signal in a second frequency band; a converter for receiving an output signal from said electronic communications device, and for converting said output

signal into said test signal ; and means for supplying said test signal to said testing device.

The above methods and systems allow for the testing of an electronic communications device using testing equipment which operates in a different frequency band than the communications device. The invention thus does away with the requirement for testing equipment which operates in the same frequency band as the device to be tested. This applies to the testing of both the uplink and the downlink path of the device to be tested.

The invention can be employed, for example, to use PCS testing

equipment (which usually operates in the 1900 MHz frequency band) to test CDMA-based mobile phones operating in the 450 MHz frequency band.

Brief Description of the Drawings An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of a system for testing an electronic communications device, in accordance with an embodiment of the invention; Figure 2 illustrates a downconverter for use in the system of Figure 1; and Figures 3 and 4 show different implementations of the system of Figure 1.

Detailed Description of the Drawings Figure 1 shows an exemplary and schematic configuration of a system for testing a CDMA mobile handset 1. The handset 1 is a CDMA-based mobile telephone which is operated at a frequency of 466.05 MHz. The system also comprises a PCS-based mobile station test set 2 which is operated at the PCS base station frequency of 1936.1 MHz (PCS = Personal Communication Service). In order to be able to use the PCS test set 2 to test the downlink path of the CDMA mobile handset 1, its output frequency is downconverted by a downconverter 3. Figure 2 illustrates the downconverter 3 in greater detail. The downconverter 3 performs the downconversion by mixing the PCS test signal with low-side injection. The low-side injection signal is provided by an external signal generator 4 whose output signal has a frequency of 1470.05 MHz. The resulting downconverted signal has a frequency of 466.05 MHz (i. e. the operation frequency of the handset 1) and is applied to the handset 1 via combiners 5 and 6 and a signal attenuator 7.

Accordingly, the present system allows testing of the non-PCS CDMA handset 1 using the PCS testing equipment 2.

Similarly, the uplink path of the CDMA handset 1 can be tested using PCS testing equipment by up converting the frequency of the output signal of the CDMA handset 1 for consistency with the PCS operation frequency. The upconversion is performed by an upconverter 8 which mixes the incoming signal from the CDMA handset I with the signal from a signal source 9.

The upconversion is again performed by mixing the input signal with low-side injection. The upband path frequency of the CDMA handset 1 is, for example, 456.05 MHz, while the designated PCS channel frequency is 1856.1 MHz. The frequency of the output signal of the signal source 9 in the given example is 1400.05 MHz. The resulting signal after mixing thus has the required frequency of 1856.1 MHz.

Thus, the present system enables test equipment operating in the PCS frequency band to be used to test mobile phones and other equipment operating in the 450 MHz band.

Figures 3 and 4 show different implementations of the system of Figure 1. Any transceiver, such as the transceiver contained in the handset 1 or the test set 2, operates on separate transmitter and receiver paths. If the handset 1 or the test set 2 use a common port, the signals on both paths must be combined. In the handset 1, the signals are combined by a duplexer (or "diplexer"). In the downconverter 3, the combination is performed by a passive combiner (which can be thought of as a splitter in the reverse configuration).

In the implementation illustrated in Figure 3, the combination is performed only at the RF interface between the downconverter 3 and the handset 1. There is no need to combine the signals at the interface between the downconverter 3 and the test set 2 since the test set 2 has separate transmitter and receiver ports.

However, some test sets, such as the test set 2 of Figure 4, have only one common port so that a combiner 10 is provided for performing the necessary combination at the interface between the downconverter 3 and the test set 2. The combiner 10 may be a separate element or integrated in either the test set 2 or the downconverter 3.

It should be noted that the present invention is not limited to the embodiment described above. In particular, the system can be used with testing equipment other than such based on the PCS standard, or with communications devices other than CDMA based handsets. Generally, the system can be used for testing electronic communications equipment operable in a first frequency using testing equipment operable in a second frequency different from the first frequency. It is envisaged that such and other modifications and variations to the above described embodiment could be made without falling outside the scope of the present invention as determined from the claims.

Claims

CLAIMS :

1. A method for testing an electronic communications device operable in a first frequency band, the method comprising: generating a first test signal in a second frequency band different from said first frequency band; converting said first test signal into a second test signal in said first frequency band; and supplying said second test signal to said electronic communications equipment.

2. A method for testing an electronic communications device operable in a first frequency band using a testing device operable in a second frequency band, the method comprising: generating an output signal in said first frequency band using said electronic communications device; converting said output signal into a test signal in said second frequency band; and supplying said test signal to said testing device.

3. The method of claim 1 or 2, wherein said first frequency band is the 450 MHz band.

4. The method of any preceding claim, wherein said second frequency band is a PCS frequency band.

5. The method of any preceding claim, wherein said electronic communications device is a CDMA-based device.

6. The method of any preceding claim, wherein said electronic communications device is a mobile telephone.

7. A system for testing an electronic communications device operable in a first frequency band, the system comprising: a first signal source for providing a first test signal in a second frequency band different from said first frequency band ; a converter for converting said first test signal into a second test signal in said first frequency band; and means for supplying said second test signal to said electronic communications device.

8. A system for testing an electronic communications device operable in a first frequency band, the system comprising: a testing device for receiving a test signal in a second frequency band;

a converter for receiving an output signal from said electronic communications device, and for converting said output signal into said test signal; and means for supplying said test signal to said testing device.

9. The system of claim 7 or 8, wherein said first frequency band is the 450 MHz band.

10. The system of any of claims 7 to 9, wherein said second frequency band is a PCS frequency band.

11. The system of any of claims 7 to 10, wherein said electronic communications device is a CDMA-based device.

12. The system of any claims 7 to 11, wherein said electronic communications device is a mobile telephone.

13. The system of claim 7, further comprising a second signal source for providing a signal of a predetermined frequency, wherein said converter comprises a mixer for mixing said first test signal with said signal of predetermined frequency to generate said second test signal.

14. The system of claim 8, further comprising a signal source for providing a signal of a predetermined frequency, wherein said converter comprises a mixer for mixing said output signal with said signal of predetermined frequency to generate said test signal.

15. The system of claim 8, wherein the testing device is arranged to transmit and receive signals on a transmitter path and a receiver path, respectively.

16. The system of claim 15, further comprising means for combining the signals on the transmitter and receiver paths at an interface between the testing device and the converter.

17. A method or system substantially as described herein with reference to the accompanying drawings.