GB2149624A

GB2149624A - Apparatus for testing electromagnetic radiation responsive devices

Info

Publication number: GB2149624A
Application number: GB08427453A
Authority: GB
Inventors: Donald Malcolm Robinson; Charles Trevor Grugan
Original assignee: Vickers PLC
Current assignee: Vinters Ltd
Priority date: 1983-11-07
Filing date: 1984-10-30
Publication date: 1985-06-12
Also published as: GB2149624B; GB8427453D0

Abstract

Apparatus for testing electromagnetic radiation responsive devices e.g. electronic surveillance measures (E.S.M.) and radar warning receiver systems (R.W.R.) on an aircraft. The apparatus consists of a shoulder pack containing a generator (1) which produces microwave test signals, and a hand held aerial head (3) connected by a coaxial cable to the generator. In use, an operator walks around an aircraft on the ground and points the aerial head at a radiation responsive device on the aircraft to emit a test emission, typically of microwave energy. The form of the test emission is selected to suit the device under test. The response of the device to the test emission can be monitored to check that the device is fully operational. <IMAGE>

Description

SPECIFICATION Apparatus for testing electromagnetic radiation responsive devices Field of the invention The present invention relates to apparatus for testing electromagnetic radiation responsive devices, and has particular but not exclusive application to testing electronic surveillance measures (E.S.M.) and radar warning receiver (R.W.R.) systems.

Background to the invention It is known that vehicles such as aircraft are provided with electromagnetic radiation responsive devices such as E.S.M. and R.W.R. systems to detect and monitor hostile aircraft or military installations.

Objects and summary of the invention An object of the present invention is to provide a portable device for testing that such radiation responsive devices are in a desired operative condition.

Another object of the invention is to provide a portable device, which can produce different test emissions for use in testing different radiation responsive devices.

The present invention provides apparatus for testing electromagnetic radiation responsive devices, comprising signal generator means for generating electromagnetic test signals, and an aerial head portable relative to the generator means and arranged to provide test emissions of electromagnetic energy as a function of said test signals.

In accordance with one aspect of the invention the aerial head includes amplifier means for amplifying the test signals from the signal generator means, and an antenna for emitting the amplified test signals. Selection of frequency bandwidth may be provided in the head by a plurality of amplifiers of different frequency pass bands and controlled switching means, for selecting the appropriate am amplifier. The controlled switching means may be operated from the generator means.

Preferably, the aerial head is configured as a hand held gun and is connected to the signal generator means by flexible waveguide means such as a coaxial cable. The gun may be provided with a trigger for operating the apparatus. The signal generator means is typically a microwave signal generator of a size which is manually portable for example in a shoulder bag, and which can produce a plurality of selectable microwave test signals.

The signal strength emitted by the head is a function of the gain of the amplifier means which has the advantage of compensating for losses which occur in the coaxial cable.

Thus, with test apparatus according to the invention, the user can point the aerial head at a radiation responsive device under test and provide a test emission for reception by the device. The response of the device to the test emission can then be monitored to determine if the device is working correctly.

Since the head is portable relative to the signal generating means, the antenna can be readily directed with a highly directional directive pattern at a plurality of different devices to be tested, for example as the operator walks around a vehicle such as an aircraft, in which the devices to be tested are located.

Brief description of the drawings In order that the invention may be more fully understood, an embodiment thereof will now be described by way of illustrative example with reference to the accompanying drawings wherein: Figure 1 is a schematic view of test apparatus in accordance with the invention, and Figure 2 is a schematic block diagram of the electrical circuits of the apparatus.

Description of preferred embodiment Referring to Figure 1, the test apparatus is shown in use for testing E.S.M. and R.W.R. systems on an aircraft. The apparatus comprises a microwave generator 1 in the form of a manually portable shoulder pack, connected by a coaxial cable 2 to an aerial head 3. The aerial head 3 is in the form of a hand held gun provided with a trigger 4 for operation of the apparatus, to avoid unnecessary microwave emission, thereby to protect the operator and save power. The head 3 includes an antenna (shown in Figure 2) for emitting microwave radiation fed to the head 3 via the cable 2.

The antenna has a directive pattern substantially only forwardly of the gun. In use, the gun 3 is pointed at the device under test and the trigger 4 is depressed so as to emit a microwave test transmission to the device. The response of the device can then be monitored to determine if it is working correctly. The form of the test transmission can be selected by controls (not shown) on the generator pack 1, so that the response of the device for a range of different test signals can be monitored.

Also, test transmissions for different devices can be selected with the controls, so that different devices can be tested on the aircraft, as the user walks around the aircraft.

The electrical circuits of the apparatus are shown in more detail in Figure 2. The circuits of the generator 1 and the hand held aerial head 3 are shown within respective hatched outlines.

The generator 1 includes a microwave oscillator 5 of any suitable type, typically operable over a range of 2 - 8 GHz and is provided with a manually operable frequency control circuit 6, to select the frequency. The oscillator is driven by a power supply circuit 7 which can be driven either from an external 250 V AC mains supply (if available) or from an internal rechargeable battery supply 8.

The output of the oscillator 5 can be modulated, for example pulse modulated by means of a modulation switch 9 under the control of a modulator circuit 10. The modulation frequency of the circuit 10 is user selectable. Also, the modulator can be switched off to provide a C.W. output. The output of the generator 1 is fed through the coaxial cable 2 to the aerial head 3. Within the head 3 are arranged first and second r.f. amplifiers 11 or 12 of different frequency bands. The r.f. input from the coaxial cable 2 is amplified by one of the amplifiers 11 or 12 under the control of switching means in the form of a relay RL having switching contacts RL1, RL2. Operation of the relay RL is controlled from the generator pack 1 through a control line 13 shown schematically. The electrical power for the amplifiers 11, 12 is fed from the pack 1 through a line 14.The lines 13 and 14 are arranged in a bundle with the coaxial cable 2.

The output of the selected amplifier 11 or 12 is fed to the antenna 15, so as to be emitted towards the device under test. The antenna 15 may emit a R.H. circularly polarised wave. The amplifiers 11, 12 have the advantage of compensating for r.f. signal losses in the coaxial cable 2, which might otherwise substantially degrade the power output from the antenna 15.

The pack 1 may be typically dimensioned 270 x 90 x 280 mm with a weight of 8 kg and is thus portable. The modulator may provide a pulse width of 0.1 s to 999.9 1S variable in 0.1 s steps, with a pulse repetition period of 0.01 ms to 99.9 ms variable in 0.01 ms steps. The carrier frequency may be tunable in 10 MHz steps.

The aerial head 3 may typically be dimensioned 100 mm in width, height 100 mm, and depth 250 mm (excluding pistol grip) with a weight of approximately 1.5 kg; it is thus readily portable and movable manually relative to the pack 1.

Claims

1. Apparatus for testing electromagnetic radiation responsive devices, comprising signal generator means for generating electromagnet test signals, and an aerial head portable relative to the generator means and arranged to provide test emissions of electromagnetic energy as a function of said test signals.

2. Apparatus as claimed in claim 1 including means for selectively varying said test signals for use with different radiation responsive devices.

3. Apparatus as claimed in claim 1 wherein the aerial head includes amplifier means for amplifying test signals from the signal generator means, and an antenna for emitting the amplified test signals.

4. Apparatus as claimed in claim 3 wherein the amplifier means includes a plurality of amplifiers having different frequency pass bands, and control means for selecting the amplifier used to amplify the test signals.

5. Apparatus as claimed in claim 4 wherein said control means comprises controlled switching means manually operable from the generator means.

6. Apparatus as claimed in claim 1 wherein said aerial head comprises a hand held gun, and including flexible waveguide means for feeding the test signals from the generator means to the gun.

7. Apparatus as claimed in claim 6 wherein the gun is provided with a manually operable trigger for controlling operation of the apparatus.

8. Apparatus as claimed in claim 1, adapted to emit microwave test emissions.

9. A Method of testing an electromagnetic radiation responsive device, with the apparatus claimed in claim 1, comprising directing the head at the device and producing a test emission therefrom, and determining the response of the device to the test emission.

10. A method according to claim 9 repeated for a plurality of said radiation responsive devices on a vehicle, including sequentially selecting test emissions appropriate for said devices respectively.

11. A method according to claim 10 wherein said vehicle comprises an aircraft and said devices are selected from E.S.M. and R.W.R. systems.

12. Apparatus for testing electromagnetic responsive devices, substantiaubstantially as herein described with reference to the accompanying drawings.

13. A method of testing electromagnetic responsive devices, substantially as herein described with reference to the accompanying drawings.