Unlike conventional RC oscillators, the DS360 uses digital signal processing and a precision 20-bit digital/analogue convertor to provide better than -100dB distortion over the audio-frequency range
The SRS DS360 function generator, now available in the UK from TTi (Thurlby Thandar Instruments), combines the performance of a low-distortion analogue source with the precision of direct digital synthesis (DDS) to achieve exceptionally low levels of distortion and noise.
With less than 0.001% total harmonic distortion (THD), 25ppm frequency accuracy, and a broad range of features including sweeps and bursts, the DS360 is an ideal signal source for use in audio-frequency research and development, manufacturing, and automated testing.
Unlike conventional RC oscillators, the DS360 uses digital signal processing and a precision 20-bit digital/analogue convertor to provide better than -100dB distortion over the audio-frequency range.
With its DDS architecture, the DS360 has the features and flexibility of a contemporary synthesised function generator, with careful shielding and board layout keeping the output noise to a minimum.
Unlike low-distortion analogue sources, which often have impressive THD specifications but suffer with poor frequency accuracy and resolution, the DS360 delivers 0.0025% frequency accuracy over its entire frequency range.
It has 6-digit frequency resolution from 1mHz to 200kHz, and a steady 25ppm frequency stability.
The DS360 generates clean sine waves and square waves, as well as a two-tone signal for IMD testing.
The two-tone signal is defined as either two sine waves, or a sine wave and a square wave.
Both frequency and amplitude are independently set for the two waves, allowing standard two-tone formats like SMPTE, DIM and CCIF to be generated.
In addition to standard waveforms, the DS360 outputs white noise, pink noise and band-limited white noise.
All functions and parameters are easily set using the front-panel keypad and spin knob.
A wide variety of amplitude units including Vrms, Vpp, dBV, dBm and dBrel can be selected.
Front-panel outputs including XLR, BNC and dual banana jacks ensure compatibility with any system.
The outputs can be configured as balanced or unbalanced, with amplitudes from 20.0uV peak-to-peak to 80.0V peak-to-peak (balanced), and 10.0uV peak-to-peak to 40.0V peak-to-peak (unbalanced).
Chassis ground and output common banana jacks are also provided.
Rear-panel digital outputs conform to AES-EBU and SPDIF/EIAJ formats.
An XLR jack is provided for the AES-EBU output, and both fibre optic and coaxial connectors are provided for the SPDIF/EIAJ output.
Unlike single-frequency analogue sources, the DS360 generates low-distortion frequency sweeps over its entire frequency range.
Linear and log sweeps are set between 10mHz and 200kHz with sweep times between 0.3ms and 100s.
Sweeps can be single-shot or repetitive, and the instrument can sweep both up and down in frequency.
The DS360 provides outstanding amplitude flatness (0.5% up to 20kHz) during frequency sweeps, and has a TTL level sweep marker output for synchronising external equipment.
It also creates tone bursts of sine waves and square waves.
The number of 'on' cycles, repetition rate, and the 'off' amplitude level can all be adjusted.
Sweeps and bursts may be triggered from the internal rate generator or an external trigger, or they can be externally gated.
The DS360 is designed for benchtop use as well as for automated testing, and has IEEE-488.2 (GPIB) and RS-232 interfaces fitted as standard.
