I/O-Module
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I/O-Module

[Important] Important

In addition to the specifications listed here, you find information on the modules and their connections in Part 1 (List of Modules) and Part 5 (Installation Guide) of this manual.

RM420-111 Digital In/Out/GPIO module, 8 channels

  • Reference level digital: 0 dbFS = full scale modulation

  • Range of frequency for measurement: 20 Hz...20 kHz

  • Latency (Digital In to Digital Out, with SRC): typ. 1,5 ms

Digital Inputs

Standard: AES3/EBU + S/PDIF (configurable in software)
Sample rate converter (SRC): avaiable, can be switched off
Sample frequency range (SRC): 30 kHz ... 100 kHz
Frequency offset (with SRC): < 0.02 dB
Input impedance: 110 Ohm (AES/EBU), 75Ohm (S/PDIF)
Dynamic range (24 bit): 140dB
THD+N (24 bit with SRC):

< -120 dB (-1 dBFS, at 0dB amplification)

< -140 dB (-60 dBFS, at 0dB amplification)

Jitter immunity: > 40 ns

Digital Outputs

Standard: AES3/EBU, S/PDIF (alternatively)
Ouput impedance: 110 Ohm (AES/EBU), 75Ohm (S/PDIF)
Dynamic range (24 bit): 144dB
Dither (configurable): off, 16, 20, 24 Bit
Jitter (internal system synchronization) < 2 ns (peak)

GPI/GPO - Control Inputs and Outputs

GPI control inputs (optocoupler, DC-insulated): external input voltage 4V...24V (DC), 4mA
4 GPO switching outputs (DC-insulated): max. 0.2A / 30V DC / 25V AC

Measurement diagram

The following diagrams were recorded with a Audio Precision System One analyzer.

Figure 10: Amplitude characteristic Sample Rate Converter, fsin = 48 kHz, fs = 48 kHz.
Figure 11: Amplitude characteristic Sample Rate Converter, fsin = 44,1 kHz, fs = 48 kHz.
Figure 12: Sample Rate Converter total distorsions (THD+N) against signal frequeny at full scale modulation –1 dB, fsin = 44,1 kHz, fs = 48 kHz.
Figure 13: Sample Rate Converter total distorsions (THD+N) against signal frequency at –60 dB, fsin = 44,1 kHz, fs = 48 kHz.

RM420-122 Mic/Headphone/GPIO module, 4 channels (up to revsion 4)

  • Reference level analog: 0 dbU = 0.775 V (RMS)

  • Reference level digital: 0 dbFS = full scale modulation

  • Frequency range for measurements: 20 Hz...20 kHz

  • Sampling frequency: 44,1 KHz...48 kHz

  • Latency (Analog In to Analog Out): typ. 1 ms

A/D-converter

Maximum input level:

18 dbU (electronically balanced)
Frequency offset: < 0,5 dB

Amplification analog

(in 5dB increments):

0 dB...50 dB
Input impedance: approx. 8 kOhm
Converter technology: 24 bit, (64 x Oversampling Sigma-Delta)
Dynamic range: 106 dB typical (A-rated)
THD+N:

< -80 dB

(-1 dBFS, at 0dB Analog Gain)

< -98 dB

(-60 dBFS, at 0dB Analog Gain)

Unbalance attenuation: > 60 dB
Crosstalk: < -90 dB
Input noise:

< -126 dBu

(200 Ohm source impedance, 50dB Analog Gain)

D/A-Converter

Maximum output level

(Headphones unsymmetrical):

15 dbU
Frequency offset: < 0,3 dB
Output impedance: ca. 17 Ohm

Load impedance

Outputs short-circuit proof:

≥ 80 Ohm
Converter technology: 24 bit, (128 x Oversampling Sigma-Delta)
Dynamic range(24 bit): 108 dB typical (A-rated)
THD+N (24 bit with SRC):

< -82 dB (-1 dBFS)

< -104 dB (-60 dBFS)

Crosstalk: < -90 dB
DC voltage offset: < 10 mV

GPI/GPO - Control inputs/outputs

2 analog control inputs (ACI - Analog Control Input):

  • Connect a linear 10 Ohm potentiometer between control input (at wiper) and ground (left fixed contact).

  • Alternatively, connect a control voltage of 0...3,3V.

  • The inputs are not DC-insulated but overvoltage-protected.

2 GPI-control inputs:

  • TTL-inputs with internal pull-up-resistor (10 kOhm to 5V).

  • Switching contact to ground or TTL level (low-active).

  • Overvoltage protected.

4 GPO-switching outputs:

  • electronic relay; DC-insulated

  • max. 0,2 A / 30 V DC /25 V AC

Measurement diagrams RM420-122 A/D-converter

The following diagrams were recorded with an Audio Precision System One analyzer.

Figure 14: RM420-122 A/D-converter: Amplitude frequency response, amplification 0dB.
Figure 15: RM420-122 A/D-converter: Total distorsions (THD+N) against signal frequency at full scale modulation –1 dB, amplification 0 dB.
Figure 16: RM420-122 A/D-converter: Signal/noise-ratio at –60dB input level (A-rated) against frequency, amplification 0 dB.
Figure 17: RM420-122 A/D-converter: Converter linearity at 1kHz, 0...-100 dBFS.
Figure 18: RM420-122 A/D-converter: Input unbalance against frequency, amplification +50 dB.
Figure 19: RM420-122 A/D-converter: Crosstalk, amplificaton +50 dB.

Measurement diagrams RM420-122 D/A-converter

The following diagrams were recorded using an Audio Precision System One analyzer.

Figure 20: RM420-122 D/A-converter: Amplitude frequency response.
Figure 21: RM420-122 D/A-converter: Total distorsions (THD+N) against signal frequency at full scale modulation (–1 dBFS).
Figure 22: RM420-122 D/A-converter: Signal/noise-ratio at –60dBFS, A-rated against freqency.
Figure 23: RM420-122 D/A-converter: Converter linearity 997 Hz, 0...-100 dBFS.

RM420-222/223 Analog In/Out/GPIO module, 4 channels

In the course of its history, DHD has developed several revisions of this module. The basic functions of these revisions are similar; but some parameters have better measurement values in later revisions. The differences are marked in the following list.

The module RM420-223 is identical with the module RM420-222, but it has a higher maximum input level.

[Note] Note

You can exchange modules of different revisions without any problems.

  • Reference level analog: 0 dbU = 0.775 V (RMS)

  • Reference level digital: 0 dbFS = full scale modulation

  • Frequency range for measurements: 20 Hz...20 kHz

  • Sample frequency: 44,1 KHz...48 kHz

  • Latency (Analog In to Analog Out): typ. 1 ms

A/D-converter

Maximum input level:

  • 18 dbU (electronically balanced)

  • 24 dbU (RM420-223, electronically balanced)

Frequency offset: < 0,1 dB
Input impedance: approx. 10 kOhm
Converter technology:

  • 24 bit, (64 x Oversampling Sigma-Delta) (until Rev. 2)

  • 24 bit, (128 x Oversampling Sigma-Delta) (since Rev. 2)

Dynamic range:

  • 106 dB typical (A-rated) (until Rev. 2)

  • 111 dB typical (A-rated) (Rev. 3)

  • 113 dB typical (A-rated) (Rev. 5,6)

THD+N at -1 dBFS: - 92 dB
THD+N at -60 dBFS:

  • -100 dB (until Rev. 2)

  • -105 dB (Rev. 3)

  • -110 dB (Rev. 5,6)

Input unbalance attenuation: > 60 dB
Crosstalk:

  • -90 dB

  • -100 dB (Rev. 3)

D/A-converter

Maximum output level:

  • 18 dbU (electronically balanced)

  • 24 dbU (RM420-223, electronically balanced)

Divergence in frequency response:

  • < 0,2 dB (Rev. 2,3)

  • < 0,15 dB (Rev. 5,6)

Output impedance: approx. 25 Ohm
Converter technology: 24 bit, (128 x Oversampling Sigma-Delta)
Dynamic range:

  • 108 dB typical (A-rated) (Rev. 2)

  • 112 dB typical (A-rated) (Rev. 3)

  • 113 dB typical (A-rated) (Rev. 5, 6)

THD+N at -1 dBFS:

  • -82 dB (until Rev. 2)

  • -85 dB (Rev. 3)

  • -90 dB (Rev. 5,6)

THD+N at -60 dBFS:

  • -104 dB (until Rev. 2)

  • -108 dB (Rev. 3)

  • -110 dB (Rev. 5,6)

Unbalance attenuation (impedance): > 60 dB
Unbalance attenuation (voltage): > 40 dB
Crosstalk: < -95 dB
DC voltage offset: < 10 mV

GPI/GPO - Control inputs/outputs

2 GPI-control inputs:

  • Optocoupler, DC-voltage insulated

  • external 4V...24V (DC) 4mA

4 GPO-switching outputs:

  • electronic relay, DC-voltage insulated

  • max. 0,2 A / 30 V DC /25 V AC

Measurement diagrams RM420-222 A/D-converter

The following diagrams were recorded using an Audio Precision System One analyzer.

Figure 24: RM420-222 A/D-converter: Amplitude frequency response.
Figure 25: RM420-222 A/D-converter: Total distorsions (THD+N) against signal frequency at full scale modulation -1 dB.
Figure 26: RM420-222 A/D-converter: Signal/noise ratio at -60 dBFS, A-rated against frequency.
Figure 27: RM420-222 A/D-converter: Converter linearity at 1 kHz, 0...-100dbFS.
Figure 28: RM420-222 A/D-converter: Input unbalance against frequency.
Figure 29: RM420-222 A/D-converter: Crosstalk between right and left channel.

Measurement diagrams RM420-222 D/A-converter

The following diagrams were recorded using an Audio Precision System One analyzer.

Figure 30: RM420-222 D/A-converter: Amplitude frequency response.
Figure 31: RM420-222 D/A-converter: Total distorsion (THD+N) against signal frequency at full scale modulation -1 dB.
Figure 32: RM420-222 D/A-converter: Signal/noise ratio -60 dBFS, A-rated against frequency.
Figure 33: RM420-222 D/A-converter: Converter linearity at 1 kHz, 0...-100dbFS.
Figure 34: RM420-222 D/A-converter: Voltage unbalance (Analog outputs) against frequency.
Figure 35: RM420-222 D/A-converter: Crosstalk between right and left channel.

Measurement diagrams RM420-223 A/D-converter

The following diagrams were recorded using an Audio Precision System One analyzer.

Figure 36: RM420-223 A/D-converter: Amplitude frequency response.
Figure 37: RM420-223 A/D-converter: Total distorsion (THD+N) against frequency at full scale modulation -1 dB.
Figure 38: RM420-223 A/D-converter: Signal/noise ratio at -60 dBFS, A-rated against frequency.
Figure 39: RM420-223 A/D-converter: Converter linearity at 1 kHz, 0...-100dbFS.
Figure 40: RM420-223 A/D-converter: Input unbalance against frequency.
Figure 41: RM420-223 A/D-converter: Crosstalk between right and left channel.

Measurement diagrams RM420-223 D/A-converter

The following diagrams were recorded using an Audio Precision System One analyzer.

Figure 42: RM420-223 D/A-converter: Amplitude frequency response.
Figure 43: RM420-223 D/A-converter: Total distorsion (THD+N) against signal frequency at full scale modulation -1 dB.
Figure 44: RM420-223 D/A-converter: Signal/noise ration at -60 dBFS, A-rated against frequency.
Figure 45: RM420-223 D/A-converter: Converter linearity at 1 kHz, 0...-100dbFS.
Figure 46: RM420-223 D/A-converter: Voltage unbalance (analog outputs) against frequency.
Figure 47: RM420-223 D/A-converter: Crosstalk between right and left channel.
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