This is a linear Class A output video amplifier with a maximum differential output of 275V over the range d.c. to ~7MHz. The two outputs can also be set to ±250V dc relative to each other using a bias control. This facility allows an electro-optic amplitude modulator to be set to any desired light output intensity level for any input signal level. This output bias does not introduce any limit to the signal output range.
The amplifier has been designed primarily to drive electro-optic modulators from the EM200 range where the load is purely capacitive and does not exceed 100pf. The output is short circuit proof.
|Signal output voltage range||275Vdc - 6MHz bandwidth|
|Amplifier Square Wave Rise & Fall Time
using 100pf load
|< 65 ns (10% - 90%)|
|Bias Voltage Range||+250V to -250V|
|Input Voltage for Full Output||±1Vdc or 2Vpp., ac|
|Input Impedance||50 ohm nominal|
|Cabinet Size (mm)||Height 220, Width 530, Length 340|
|Mains Voltage||110/200/240ac 50-60Hz|
|Temperature Range||0° - 40°C ambient|
One area in which the M250 amplifier has found much use over the years is in driving modulators used for intensity noise reduction of CW lasers, so called "noise-eating" applications. The high bandwidth of the amplifier combined with a low resonance modulator such as the EM200A provides the ideal control element to apply the required intensity correction signal as determined by a suitable optical pickup circuit.