Hardware Specifications¶
The BBN Arbitrary Pulse Sequencer 2 (APS2) is a modular system providing up to 18 channels of analog waveform generation with a maximum output rate of 1.2 GS/s and 14-bits of vertical resolution. Each module in an APS2 system provides two analog outputs, DC coupled into a fixed +/- 1V range, and four digital outputs (1.5 V) for triggering other equipment. Each APS2 module has 1 GB of DDR3 SDRAM for waveform and sequence storage, which is enough for over 64 million sequence instructions. A low-latency cache allows for fast access to 128K waveform samples. Each module can be independently triggered for sophisticated waveform scenarios.
The digital and analog circuits have been carefully engineered to provide extremely low-noise analog performance, resulting in a noise spectral density that is orders of magnitude lower than competing products, as shown in Noise Comparison.
Detailed Specifications¶
Analog channels | two 14-bit 1.2 GS/s outputs per module |
Digital channels | four 1.5V outputs per module |
Analog Jitter | 7.5ps RMS |
Digital Jitter | 5ps RMS |
Rise/fall time | 2ns |
Settling time | 2ns to 10%, 10ns to 1% |
Trigger modes | Internal, external, system, or software triggering |
Ext. trigger input | 1 V minimum into 50 Ω, 5 V maximum; triggered on rising edge |
Reference input | 10 MHz sine or square, 1V to 3.3V peak to peak (+4 to +14 dBm) |
Waveform cache | 128K samples |
Sequence memory | 64M instructions |
Min instruction duration | 8 samples |
Max instruction duration | 8M samples (~7ms at 1.2GS/s) |
Max loop repeats | 65,536 |
Triggering¶
The APS2 supports four different types of triggers. The internal mode generates triggers on a programmable interval between 6.66ns and 14s. The external mode listens for triggers on the front-panel SMA “trigger input” port. In this mode, the APS2 is triggered on the rising edge of a 1-5V signal. The system trigger accepts triggers on the SATA input port from the APS2 Trigger Distribution Module (TDM). Finally, the software mode allows the user to trigger the APS2 via the host computer with the trigger() API method.
Communications Interface¶
The APS2 communicates with a host PC via UDP/TCP over 1GigE. 1GigE is required so ensure all switches between the host computer and APS2 support 1GigE. The APS2 supports static and DHCP assigned IP addresses. Instructions for setting the APS2 IP addresses are contained in the Software section.
Status LED’s¶
The L1 and L2 LEDs provide status indicators for the communication (L1) and sequencing (L2) firmware components.
L1:
- off - SFP port failure
- green breathing - no ethernet connection;
- solid green - link established (but not necessarily connected to host);
- green blinks - receiving or transmitting data;
- red - fatal communication error. Power cycle the module to restore connectivity.
L2:
- dark - idle;
- solid green - playback enabled and outputing sequences;
- green breathing - playback enabled but no trigger received in the past 100ms;
- solid red - fatal cache controller error. Power cycle the module to restore playback functionality.
- blinking red - cache stall in playback. See cache for details.