| 摘要 |
A circuit is provided for eliminating the effects of spurious signals from a pyrometer in a gas turbine engine. The pyrometer signal is fed to a part of the circuit (8,12,16,20,24) which produces an inverted and rate limited output signal c representative of the pyrometer output signal. Signal c is fed back to the input of amplifier 8 and is subtracted from it and amplifier 8 outputs a positive or negative signal depending on whether or not its input is positive or negative. The output is passed to a positive edge triggering device 28 which triggers a sample and hold device 30 the output of which constitutes the output of the circuit. When the pyrometer signal increases very rapidly due to a spurious signal, the input to the amplifier 8 rises more rapidly than the rate limited feedback from amplifier 12 so that the output goes positive to trigger device 28 and remains positive until the spurious signal has died away. The sample and hold device 30 thus holds the last sampled pyrometer signal and is not affected by the spurious signal.
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