For the first time in an oscilloscope, Pico Technology has used reconfigurable ADC technology to offer a choice of resolutions from 8 to 16 bits in a single product.
Most digital oscilloscopes gain their high sampling rates by interleaving multiple 8-bit ADCs. Despite careful design, the interleaving process introduces errors that always make the dynamic performance worse than the performance of the individual ADC cores.
The new PicoScope 5000 Series scopes have a significantly different architecture in which multiple high-resolution ADCs can be applied to the input channels in different series and parallel combinations to boost either the sampling rate or the resolution.
In series mode, the ADCs are interleaved to provide 1 GS/s at 8 bits. Interleaving reduces the performance of the ADCs, but the result (60 dB SFDR) is still much better than oscilloscopes that interleave 8-bit ADCs. This mode can also provide 500 MS/s at 12 bits resolution.
In parallel mode, multiple ADCs are sampled in phase on each channel to increase the resolution and dynamic performance. Resolution is increased to 14 bits at 125 MS/s per channel (70 dB SFDR). If only two channels are required then resolution can be increased to 15 bits, and in single-channel mode all the ADCs are combined to give a 16-bit mode at 62.5 MS/s.
Pico has over 20 years’ experience in the design of high-resolution oscilloscopes but, even so, developing a new analog front end to support an oscilloscope that can be switched between different resolutions was a significant challenge. Careful attention was required to support the high-resolution modes (with low noise, low distortion and bandwidth flatness) while maintaining the bandwidth, slew rate and pulse response necessary for the faster 8-bit mode.
As well as flexible resolution, these oscilloscopes have ultra-deep memory buffers of up to 512 MS to allow long captures at high sampling rates. They also include, as standard, advanced software features such as serial decoding, mask limit testing and segmented memory.