M405 datasheet(41/89 Pages) BK

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* Differing from base band at which the up-conversion of input frequency is done with a frequency mixer, the

spurious response peculiar to band 1- and band 1+ is generated because the down-conversion is done at those

two bands.

* About SPURIOUS FREE mode

1. SPURIOUS FREE mode is a mode by which the spurious response peculiarly caused at band

1+ is simply deleted.

2. SPURIOUS FREE mode is especially effective in the measurement of a stationary wave.

3. If SPURIOUS FREE mode is used in measurement of a signal with level change or frequency

change, the phenomenon that the level goes down will occur.

4. The noise level goes down a little in case of a noise changing at random. In short, the same

phenomenon as MIN HOLD function happens.

* How to judge SPURIOUS response at band 1- and band 1+

The procedure for judging SPURIOUS response at band 1- and band 1+ is as follows.

1. Set the center frequency to < (current setting value) + f >.

2. The spectrum shifting left by f is a correct spectrum, but another spectrum shifting such as left

by 2f, left by 3f, right by f, right by 2f or right by 3f is a spurious response.

* “f ” should be changed according to SPAN for easy judgment. For reference;

f = SPAN / (10 to 50) (corresponding to 0.2 to 1 div)

Example: judging a spectrum displayed at 6.92 GHz

(setting : center frequency 6.92 GHz and SPAN 500 MHz)

1. Set the center frequency to < 6.92 GHz + 500 MHz/25 > = 6.94GHz.

2. A spectrum at 6.92 GHz (shifting left by f from 6.94 GHz) is correct. A spectrum at 6.98 GHz (shifting

right by 2f from 6.94 GHz) is spurious.

* Additionally, a spurious response mentioned above shifting right by 2f at band 1+ is largest, and other

spurious response are about 25 to 50 dB smaller than that.

17. Marker & Peak Search <MKR>

When

is pushed, the following function menu is displayed.

● Main menu ofmarker function

CONV

dBm

→W

NORMAL

MARKER

DELTA

OFF

CENTER FREQ

NORMAL

ZONE

MKR

M405 Datasheet(PDF) 41 Page - B&K Precision Corporation