Pulsemaster Multi-Channel Stimulator
The Pulsemaster™ (Model A300) is WPI™s third generation, multichannel, pulse/train generator/stimulator that combines the superb accuracy of digital electronics with the you-see-what-you-get displays only available on single-channel products. In one compact rack mountable enclosure, the Pulsemaster contains an event interval generator, five pulse train channels, two mixing channels and a very quiet variable voltage output channel. System timing is accurate to 100 ppm; output timing is continuously variable in 0.1% of full scale increments over a range of eight orders of magnitude. Bright, three-digit LED displays continuously and simultaneously show all the variable timing parameters. The Pulsemaster is designed for ease of use and flexibility. Each channel can be operated synchronized with the onboard event interval generator, triggered manually from any other channel or external source, and as an independent asynchronous pulse generator. Except for the external source, all channel interconnections are accomplished on the panel, without the use of cables. The output from each channel is compatible with standard digital circuitry and is also designed to drive WPI’s A300 series stimulus isolators. If desired, any channel’s output may be internally connected to the variable channel, whose amplitude can be continuously adjusted from millivolts to ten volts.
The Event Interval
The EVENT INTERVAL is the heartbeat of the Pulsemaster. Based on a highly accurate and stable crystal oscillator, the EVENT INTERVAL generates synchronization pulses at regular intervals. The width of the sync pulses is fixed at approximately 6µs, but their repetition interval is panel adjustable from 10µs to 999s, using the display and its associated switches. Sync pulses may also be generated at random or irregular intervals by using the SINGLE EVENT or the EXTernal SYNC mode. The sync pulses are internally distributed to the five PULSE TRAIN channels and are also available externally through the SYNC OUT connector.
The Pulse Train
There are five PULSE TRAIN channels in the Pulsemaster. Except for sharing a common power supply, each is an independent instrument. Each channel has two adjustable timing parameters, DELAY and WIDTH, which in combination with internal or external signals may be used to create a variety of pulse and train waveforms. DELAY and WIDTH parameters can be changed while the instrument is operating.
The basic difference between PULSE and TRAIN modes is the number of pulses that can be generated per sync pulse. In PULSE mode, only one pulse is generated for each sync pulse. As the sync pulse is received from one of the selected input sources, the leading rising edge of the pulse is recognized and a DELAY time/pulse WIDTH pair is generated. In TRAIN mode, multiple pulses can be generated per sync pulse. As in PULSE mode, as the leading rising edge of the sync pulse is recognized, a pulse WIDTH/DELAY pair is generated. Pulses (WIDTH/DELAY pairs) are continuously produced as long as the sync pulse is still “high” at the conclusion of the DELAY time.
By means of the INPUT SELECT switch, sync pulses can be received from an external source through the EXT SYNC connector, manually by the SINGLE switch, from any of the other PULSE TRAIN channels, or one of the MIXER channels. The channel may also be disabled by switching to one of the OFF positions.
EXT SYNC position: permits control of the PULSE TRAIN channel by other instruments and computers.
SELF SYNC position: the channel becomes a free running pulse generator. The symmetry of the waveform can be adjusted by varying the DELAY and/or the WIDTH times.
SINGLE EVENT position: pulses are generated at your discretion. Every time the SINGLE button is pressed, one and only one DELAY/WIDTH sequence is generated.
EI position: connects the output of the EVENT INTERVAL generator to the input of the PULSE TRAIN channel. For every output sync pulse from the EVENT INTERVAL generator, one DELAY/WIDTH pair is generated.
PT positions (4): internally connect the outputs from the respective PULSE TRAIN channels to the input of this PULSE TRAIN channel. In the PULSE mode, for every OUTPUT pulse from the other selected PULSE TRAIN channel, one DELAY/WIDTH pair is generated from this channel. In the TRAIN mode, pulses are generated from this channel as long as the pulse from the other channel remains “high.”
MIX positions (2): internally connect the outputs from the respective MIXER channels to the input of this PULSE TRAIN channel. In the PULSE mode, for every OUTPUT pulse from the MIXER channel, one DELAY/WIDTH pair is generated from this channel. In TRAIN mode, pulses are generated from this channel as long as the pulse from the MIXER channel remains “high.”
OUTPUT connector: supplies the waveforms generated by the PULSE TRAIN channel. This OUTPUT is designed to drive WPI’s A300 series stimulus isolators. It is also useful for synchronizing other instruments (recorders, oscilloscopes, computers, etc.) with the pulses generated from the Pulsemaster.
The Mixer
The MIXER does what its name implies, it combines any or all of the outputs of the PULSE TRAIN channels with external signals into one waveform. It can also provide a continuous (DC ON) or momentary (DC MOM) “high” level signal. The Mixer OUTPUT connector supplies the combination waveforms generated by the MIXER channel to drive WPI’s A300 series stimulus isolators or to synchronize the operation of other instruments with the Pulsemaster.
The Variable Channel
The VARIABLE channel can replicate the OUTPUT waveforms from any of the PULSE TRAIN or MIXER channels at amplitudes that can be varied from millivolts to ten volts. The channel also provides a very low noise, adjustable DC voltage source: the DC mode which converts the VARIABLE channel into a constant voltage source. The OUTPUT connector supplies the amplitude modified waveform or the DC voltage level of the VARIABLE channel.