singmai SM13 HD-SDI Attenuator User Manual
- June 8, 2024
- singmai
Table of Contents
singmai SM13 HD-SDI Attenuator
Revisions
| Date | Revisions | Version |
|---|---|---|
| 07-11-2022 | First draft | 0.1 |
Introduction
SM13 is an HD-SDI / SDI attenuator designed for testing the robustness of
serial digital interface (SDI) links. The SDI input can be attenuated by up to
32dB in 1dB steps, selected using binary weighted switches. SM13 may also be
used for testing other RF links up to 2GHz in bandwidth (e.g. aCVi)
SM13 requires 5VDC which is provided via the supplied AC-DC converter.
Quick start guide
Connect the SM13 to the supplied AC/DC adaptor. The adaptor should be supplied
with a power lead appropriate to your country. The adaptor accepts AC between
100 and 240VAC – the full specification is provided in Appendix A. Connect the
5VDC jack from the adaptor to the +5VDC ‘Power in’ socket on the SM13. Connect
an SDI video input to the ‘SDI In’ BNC – SM13 supports SMPTE 259M and SMPTE
292M. SDI Out is an attenuated copy of the input. With all the switches off,
the output is attenuated by 1.0dB the insertion loss). The switches introduce
the stated attenuation in the output signal. For example,
turning ‘16dB’ switch on introduces 17dB of attenuation (16dB + 1dB insertion
loss). Switching on ‘16dB’ and ‘2dB’ attenuation will add 19dB of attenuation
(16dB + 2dB + 1dB insertion loss). The switches act immediately on the signal.
SM13 Connections.
SM13 Technical Details
A simplified block diagram of the SM13 is shown in Figure 2. SM13 Block
diagram.
The +5VDC from the AC/DC power adaptor is filtered and protected from over-
range or reverse polarity inputs by a resettable fuse. This fuse will protect
the SM13 until the out-of-range condition is removed when it automatically
reset itself. The 5VDC input is then regulated to provide a ‘clean’ 3.3VDC
supply for the module. The SDI input/output signal path is 75Ω impedance. An
RF attenuator can attenuate the input signal by up to 32dB in 1dB steps. Any
RF signal may be applied to the SM13 providing it is within the bandwidth and
input levels shown in the specification.
Specification
- **** Power: +5VDC ± 5% @ ~100mA (all outputs driven).
- Dimensions: 80mm x 54mm x 25mm.
- Video input: Supports SMPTE 259M and standards.
- Bandwidth: 2MHz – 2GHz ±0.5dB.
- Input/output return loss: Better than -15dB.
- Input level: TBA.
- Operating temperature: -10 – 40 degC.
Appendix A: AC-DC adaptor
The specification for the supplied AC-DC adaptor is shown in Figures 3-5.
Power supply specification – Page 1. Power supply specification – Page 2.
Power supply specification – Page 3.