> > As you have an oscilloscope first check the signal from the camera is to
> > specification i.e. 1 volt peak to peak comprising 0.3 volt sync pulses
and 0
> > to 0.7 volt video.
>
> I will do this, but first...
>
> > Have you terminated the video camera ?
>
> Since I don't know what you mean, I'd have to answer no. :)

Analogue Video Sources consist of a 2 volt peak to peak generator with a 75
ohm source impedance to match the 75 ohm coaxial cable used to interconnect
equipment. The end of the cable must be terminated in 75 ohm for correct
operation. Domestic equipment capable of accepting video such as a TV or
Video Recorder have these 75 ohm terminations inbuilt. Professional and
Semiprofessional equipment have an input and output socket which are
connected together internally allowing equipment to be daisy-chained with
the last piece of equipment being terminated in 75 ohm. This type of
equipment usually has an input impedance of around 10k ohm or more although
I have met equipment with less.
>
> I will tell you what I have done:
>
> 1. The camera I am using works (ie displays a good picture when hooked to
> a TV)

Because the TV has inbuilt terminations
>
> 2.  When I conect it to the 1881 I hook it up as follows:
>
> The outside ring of the RCA connector gets grounded to the power supply
> ground (is this correct?)
>
> The inside pin part of the RCA connector is hooked to a 0.1 microfarad
> cap, which is then connected to pin 2 of the 1881.  Additionally a
> low-pass filter (as per datasheet) that consists of a 660 ohm resistor (?)
> in in series with the signal, and an additional 550 picoF (?) cap to
> ground.
>
> Does this qualify as terminating the video camera?

No it qualifies as High Impedance (sort of)
>

This two camera module you have, presumably it has a synchronising pulse
generator which keeps the two cameras in sync. Why cannot you access these
signals to provide the switching ?

Chris

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