Vivitar DVR 830XHD Owner's Manual page 62

Select the light frequency for the local environment. Generally, 60HZ is for the
U.S. and 50HZ for Europe and Japan.
1.
Push the OK joystick button Up/Down to select the Frequency mode.
2.
Push the OK joystick button Right for the Frequency options submenu to
appear:
50Hz , 60 Hz.
3.
Push the OK joystick button Up/Down to highlight and select the
Frequency option you desire.
4.
Press the OK button to confirm and save your choice.
5.
Press the Menu button to exit.
Date / Time
Set the Date and Time for your camera.
1.
Push the OK joystick button Up/Down to select the Date / Time mode.
The default setting is 60HZ
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