Dynamic Reserve

Sensitivity Range

LOW

1 V through 500 mV

NORM

100 nV through 50 mV

HIGH

100 nV through 5 mV

Dynamic Reserve

The dynamic reserve (DR) is set using the keys in the DYNAMIC RESERVE section. The reserve is displayed by the three indicator LED's,HIGH, NORM, LOW. Only those dynamic reserve settings available for the sensitivity are allowed (see above table). For example, when the sensitivity is 500 mV, the DR will always be LOW.

The dynamic reserve and output stability of each setting are shown below.

Setting

Dynamic Reserve

Output Stability

 

 

(ppm/°C)

LOW

20 dB

5

NORM

40 dB

50

HIGH

60 dB

500

Since a higher DR results in degraded output stability, you should use the lowest DR setting for which there is no overload indication. Note that using the Bandpass Filter provides about 20dB of additional DR and so allows you to operate with a lower DR setting.

Status

There are five STATUS LED's.

OVLD indicates a signal overload. This condition can occur when the signal is too large, the sensitivity is too high, the dynamic reserve is too low, the offset is on, the expand is on, the time constant is not large enough, or the ENBW is too large.

UNLK indicates that the reference oscillator is not phase locked to the external reference input. This can occur if the reference amplitude is too low, the frequency is out of range, or the trigger mode is incorrect for the reference signal waveform.

ERR flashes when an error occurs on one of the computer interfaces, such as an incorrect command, invalid parameter, etc.

ACT indicates activity on the computer interfaces. This LED blinks every time a character is received by the SR510 or transmitted by the SR510.

REM indicates that the unit is in the remote state and that the front panel controls are not operative. There are two remote states. The Remote-With- Lockout will not allow any inputs from the front panel. The Remote-Without-Lockout command allows you to return the front panel to operation by pressing the DISPLAY UP key.

Diplay Select

The keys in the DISPLAY section select the

parameter to be displayed on the output meters and the output on the OUTPUT BNC connector.

The displayed parameter is indicated by one of the three LED’s and can be either the demodulator output (X), the offset (OFST), or the rms noise (NOISE). When displaying NOISE, the equivalent noise bandwidth (ENBW) is selected in the TIME CONSTANT section.

Output

The analog output is available at the OUTPUT BNC. The input signal equal to the selected full scale sensitivity will generate a ±10V output when the EXPAND function is off. With the EXPAND on, the output is multiplied by 10, effectively increasing the full scale sensitivity by 10. The ouptut impedance is <1and the output current is limited to 20 mA.

The analog meter always displays the OUTPUT voltage. Accuracy is 2% of full scale.

The OUTPUT LCD display provides a read-out of the displayed parameter in real units. The scale of the displayed quantity is indicated by the three scale LED's to the right of the display. This readout auto ranges and will reflect the sensitivity added when the EXPAND function is on.

Expand

The output EXPAND is toggled by pressing the key in the EXPAND section. The expand status is indicated by the X10, expand on, and the X1, expand off, LED's.

REL Function

The relative (auto-zero) function is toggled by the key in the REL section. Every time the rel status LED is turned ON the offset value is set to minus the value of the X output, thus zeroing the X output. This function will work even if X is not the

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