DS8000 8-channel stimulator

The world's most advanced digital stimulator amplifier
  • Single board computer w/ LCD touch screen
  • Scope mode displays waveforms
  • 8 banks of 3 timers, synchronous / asynchronous
  • 8 internal and 8 external trigger inputs
  • 32 separate outputs ( 24 BNC's front panel )
  • Lifetime firmware upgrades via serial / Ethernet
  • Unipolar, bipolar, paired pulse, sine, ramp, custom
  • Custom upload of real biopotentials
  • 3 independent full parameter memory banks
  • GLP / GCP compliant w / password protection

The DS8000 represents a quantum leap in the performance of the research stimulator, and is the most advanced stimulator on the market.  With a built-in computer, the entire waveform is generated digitally with precision timing. The DS8000 can generate stimulating wave patterns of a complexity unmatched by any other instrument on the market. A built in digital oscilloscope allows the user to preview waveforms on the LCD. An Ethernet connection allows the user to transfer custom waveforms and upgrade the software using TCP/IP protocol via remote access.

The DS8000 has 8 analog outputs, 8 TTL outputs and 8 combined analog or TTL outputs. Each combined output can be comprised of a combination of any of 1 to 8 channels. Eight independent internal timers and eight independent external triggers are offered.  The built-in waveforms include unipolar, bipolar, and paired pulse, as well as step, sine, ramp and custom. An external trigger, internal analog channel, internal TTL channel, or any of the eight built-in timers can be assigned to control each output channel.

A unique feature of the DS8000 is the capability to stimulate with a waveform that is identical or similar to real biopotential wave patterns associated with ECG, EEG or action potentials. A biopotential waveform captured by a data acquisition system may be transferred to an Excel spreadsheet for editing or modification, then loaded into to the DS8000.
One of the main problems of designing a stimulator is that a user might want very different stimulating patterns for different research applications.  In order to satisfy all of these needs, traditional logical circuit based stimulators have control panels that use buttons and knobs to give the user as much control options as possible. However, even with a full panel of buttons, the selection of the stimulating pattern is still very limited. These types of stimulators can not generate complicated waveforms, such as combination pulses at varying interpulse intervals and amplitudes. Although microprocessor-based stimulators have made a significant step in solving these problems, certain complex waveforms are still impossible to generate.  In fact, this decade old technology has serious limitations since each control button has been programmed to perform multiple functions. Moreover, it can only display limited lines of scrolled text—no graphics! To complicate matters, it is almost impossible to upgrade the software with new functions once the instrument has been manufactured; even the programming is awkward.

The DS8000 overcomes the hardware limitations of other types of stimulators by being reliant on a flexible software-timing interface. The user can then apply this dynamically to almost any kind of stimulation protocol without being restricted by the hardware limitations of the traditional logical circuit based stimulators. In order to suit complex custom protocols, the DS8000 is designed to offer a unique flexibility by simply reprogramming the pattern output using a few keystrokes under pull-down menus.

Although it may be argued that some functions of the DS8000 can be implemented on a standard PC, it is important to recognize that the inherent design of a PC operating system makes the accurate delivery of precision pulse protocols impossible. Despite the fact that PCs are very economical, they are simply not designed to generate highly accurate timing because the microprocessor resources are not prioritized for this function. In addition, analog waveform generation is not readily available without adding expensive output boards and the required programming is non-standard. The DS8000 platform is based on a powerful single board computer that is fully dedicated to the temporal accuracy and precision required in current biological and neurological research. Indeed, the DS8000 Digital Stimulator offers all of these solutions plus Good Laboratory Practices (GLP) compliance for research traceability.
DS8000 — there is no competition!
Paried Pulse Protocol
The DS8000’s Paired Pulse function allows the user to generate triggered paired pulses (including refractory period) from a single channel without the use of a train function. WPI’s paired pulse algorithm simplifies the arduous repetitive task normally associated with manual resetting of interpulse intervals in refractory studies. Auto-increment eliminates the need to overlap train functions from multiple channels to generate a complete protocol. Thus, there is a significant reduction in setup time and a minimization of the potential for human error during interactive protocol modification.  
Fig. 1 shows Channel 1 configured in the TRIGGERED PAIRED PULSE mode.  In this example, a dual pulse event occurs synchronously with each trigger pulse from Channel 8, which is set to trigger every 300 ms. The initial interpulse interval is set to 20 ms.  Subsequent interpulse intervals are automatically incremented by 35 ms for each three consecutive paired pulse events. The resulting paired pulse is displayed in the lower trace on the DS8000 scope (Fig. 2). The upper trace shows the master trigger pulse set up on Channel 8.

Soft Keys and GUI interface
The DS8000 employs “soft keys”, which are programmable controls widely used in several menu options to sequentially change the numerical value of any variable waveform parameter. The DS8000’s soft keys are easily recognized as single or double “+” and “-“ signs located adjacent to a parameter value box (Fig. 1). Soft keys provide quick and easy access to modify parameter values on the fly during an experiment. The GUI interface (Fig. 3) enables the user to assign the incremental value of the soft key to suit the needs of the experiment. Alternatively, a pop-up numeric keypad is accessible for each parameter to program a precise value that is not a multiple of the softkey-preset increment.
Combined Channel Assignment matrices
The CTTL (COMBINED TTL matrix) and CA (COMBINED ANALOG matrix) screens permit the assignment of any combination of the 8 available TTL or Analog signals to any permutation of  the respective (8) CTTL or (8) CA BNC outputs. The setup in Fig. 4 indicates that all TTL channels are assigned to their respective CTTL outputs with the exception of  the output of CTTL 1, which is assigned a combination of the TTL signals from channels 4 and 5. Changing assignments is as easy as checking the associated box. The CA tab reveals an identical matrix for programming the COMBINED ANALOG BNC outputs.

Fig. 1

Fig. 2

Fig. 3

Fig. 4
SOFTWARE DOWNLOAD
Version 1.2.1
DS8000 Specifications
Timing parameters
 
Period (total signal width) 0.04 ms to 10,737,418.24 ms
Pulse width 0.02 ms to 10,737,418.24 ms
Bipolar gap width 0.00 ms to 10,737,418.24 ms
Operating Modes Free run, triggered, gated, Train, DC
Triggers 8 External, manual, TTL 1-8, combined TTL 1-8, timer start or stop
Train events 1-200
Train pulse width 0.02 ms to 10,737,418.24 ms (3 hours)
Train pulse DELAY 0.04 ms to 10,737,418.24 ms
Train period 0.06 ms to 10,737,418.24 ms
NC Output connectors Analog, combined analog, combined digital (TTL)
Waveforms Unipolar, bipolar, rectangular, sine, ramp, step, paired pulse, custom defined
Custom waveform 12 steps/ voltage point (1025 if remote controlled)
VARIABLE step waveform 100 points (1025 if remote controlled)
Output Noise < 5 mV rms
Timing Accuracy < 100 ppm
OUTPUT Voltage Resolution 5 mV
Max. output voltage +/-10V @ +/- 10 mA @ 0.005 V/step
Output impedance 50 Ohm Analog, < 1 ohm Combined Analog
External TRIGGER sync 40 µs minimum pulse TTL, CMOS 20 µs glitch and spike protection
Digital I/O 5V max 10 mA (input)
Mains voltage 85-260 V AC, 45-65 Hz 50W
EMC CE
Dimensions 13.3 cm x 42.5 cm x 25.4 cm 5.25” x 16.73” (19” rack) x 10”
Weight Approximately 4.0 kg (9 lb)
Ambient temperature -10 to +40 °C; -20 to +50 °C (Internal)
Humidity Max. 95% relative humidity, non-condensing
SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE.