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Äàòà èçìåíåíèÿ: Fri Jul 26 19:37:25 2002
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Receiver crosshead modulation of the gain.

july,2002

Total power data was taken with the xband receiver. A 40 Mhz band at 8800 Mhz was square law detected with a 20 millisecond time constant and then sampled at 100 hz with the 12 bit A/D converters. About 40 seconds of data was taken. The plot shows a 1.2 hz variation in the total power.

The top plot is a time series of the total power data data (PolA) smoothed to 3 hz.
The bottom plot is a fourier transform of the time series showing the peaks at 1.2 and 2.4 hz. The 1.2 Hz is about .001 of Tsys.

1.2 Hz is the period of the crosshead used to cool the amplifier. This variation should be checked on the other receivers.

processing: x101/020724/rcvrcrossheadcycle.pro

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