CED 3505 Programmable attenuator

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The CED 3505 and 3505HP are single-channel programmable attenuators offering main attenuations from 0dB to over 100dB in 2.5, 3 or 5dB steps. Other attenuation ranges are available to special order.

Control of the attenuation and other programmable features of the 3505 is via an internal USB-serial port. It may be controlled by scripts in Spike2 or Signal. Fast attenuation changes may also be implemented via a parallel port designed to interface with a CED1401 digital output. In this way, the sequencer facility in the CED Spike2 software package can control the attenuation for real-time synchronisation under experimental conditions. The standard 3505 has an additional output connector producing an “attenuation changed” pulse.

3505HP Headphone output

In the 3505HP model, this connector is replaced by a 6.3mm stereo jack socket. The jack socket carries the output from an internal audiometric headphone amplifier, designed to drive standard audiometric headphones to sound pressure levels of around 140dB. The attenuator output signal can be routed to one or both headphones, and there is an independent calibration attenuator for each headphone channel.

3505B Balanced output

The 3505B adds an I/O card, designed to maximise the signal-to-noise ratio at the 3505 attenuator output, particularly useful when using higher attenuation settings. The card implements differential inputs and outputs for the analogue signals to and from the attenuator, giving an improvement in signal-to-noise ratio of around 30dB.

Details

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Box size:

240mm x 240mm x 46mm (W x D x H), external mains-driven power supply.

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