AD3100 Audio Delay/Synchronizer
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Discontinued Product.
Complete technical support provided for units sold.


Automatic lip sync correction
Pitch correction up to +/- 25%
Delay range of 6.144 seconds for obscenity screening
Analog inputs and outputs
AES/EBU, SMPTE and S/PDIF digital inputs and outputs
Sample rate conversion between digital formats


The AD3100 Digital Stereo Audio Processor is a flexible, multi-function device that is ideally suited to applications in both audio, and video/audio production and post-production. With both analog and digital inputs and outputs, the AD3100 is at home in analog, digital and hybrid installations. The AD3100 can be used as: a variable audio delay for automatic lip sync correction; a variable pitch corrector; a fixed audio delay of up to 6.144 seconds (adjustable in 1 mS increments) for obscenity screening, or other audio delay requirements; a sample rate converter between professional and consumer digital audio formats; a "bridge" between analog and digital audio systems.

The pitch shifting feature of the AD3100 corrects audio pitch errors of up to +/- 25%. A typical source of these errors is off-speed playback from a telecine for film/PAL video conversion, VTR, or other audio sources. The amount of pitch shift applied to the input can be set in increments of 0.1%.

When used for lip sync correction, the pitch shift feature allows the AD3100 to rapidly track a video delay change (such as the 1 or 2 frame shift that occurs with pointer crossover in a video frame synchronizer). The pitch shifter is enabled automatically to add a shift that is equal and opposite to the shift caused by the changing delay. Conventional correctors typically restrict the rate of delay change under these conditions which can leave the audio out of sync for many seconds, or even minutes after the video delay change has occurred.

Lip sync correction is completely automatic when the delay of the AD3100 is controlled with a control pulse from compatible video frame synchronizers, such as the Pixel Instruments DS4200, VS5200, or VS2100. If your video processor does not provide a delay control pulse, the Pixel Instruments DD2100 or DD3100 Video Delay Detector can be used to measure the actual video delay and "steer" the AD3100.

The AD3100 has AES/EBU, SMPTE and S/PDIF (consumer) digital audio inputs and outputs. The input and output sample rate can be chosen from 32 kHz, 44.056 kHz, 44.1 kHz or 48 kHz. The output sample rate can be the same as the input (automatic mode), or can be independent of the input for inter-format applications. For video installations, where it is important that the audio and video sample rates be synchronized to a common reference, the AD3100's output sample rate can also be frequency locked to an internal crystal or to an NTSC or PAL video reference.

In an obscenity screening application, pressing the "Dump" button on the front panel, or a remote "Dump" button causes an instant zero delay, censoring the unwanted audio in memory. After the button is released, the delay is increased at a controlled rate, quickly restoring the original setting. During delay changes, the pitch shifter minimizes pitch modification of the audio.

The front panel of the AD3100 includes an LCD mode/status display, dual bargraph audio level display and gain trim controls for the analog input and output. Performance specifications are exceptional for both the analog and digital paths. For analog input/output, 20 bit linear PCM with 64x oversampling results in a flat frequency response and wide dynamic range. Digital input/output is essentially transparent, within the limitations of the format selected.


Pitch Correction
Adjustable from 0 to +/- 25% in 0.1% increments

Delay Setting
Adjustable from 0 to 6.144 sec in 1 mS increments

Rate of Delay Change
Adjustable from 0.2% to 10% in 0.1% increments

Analog Input & A/D Conversion
Connector/Configuration 2 x 3 pin XLR/Balanced
Impedance 20 k/600O, selectable
Full scale input level +28/+24/+20 dBu, selectable
Input gain trim 0 to -20 dB
Encoding format 20 bit linear PCM, 48 kHz sample rate
Delta-sigma modulation, 64x oversampling

D/A Conversion & Analog Output
Connector/Configuration 2 x 3 pin XLR/Balanced
Impedance 24 maximum
Full scale output +28/+24/+20 dBu into 600O, selectable
Output gain trim 0 to -20 dB
Encoding format 20 bit linear PCM, 48 kHz sample rate
8x oversampling

Digital Inputs & Outputs

AES/EBU 3 pin XLR/110O balanced
SMPTE BNC/75O unbalanced.
S/PDIF RCA Phono/75O unbalanced.
Sample rates 48 kHz, 44.056 kHz, 44.1 kHz, 32 kHz
Output sample rate may be independent of the input sample rate
Video reference 15,734.26 kHz (NTSC) or 15,625 kHz (PAL)

Performance - Analog Input to Analog Output
Frequency response < +/- 0.1 dB, 20 Hz to 20 kHz
Dynamic range > 97 dB, 20 Hz to 20 kHz, unweighted
THD + Noise < .005%, 20 Hz to 20 kHz, unweighted
SMPTE IM < .015%
Channel separation > 80 dB, 20 Hz to 20 kHz
Channel phase match < +/- 1o, 20 Hz to 20 kHz
Transport delay < 1.5 mS
(All measurements made at +24 dBu, fixed audio delay, zero pitch shift)

Performance - Digital Input to Digital Output
Frequency response < +/- 0.01 dB, 20 Hz to 20 kHz
Dynamic range > 117 dB, 20 Hz to 20 kHz, unweighted
THD + Noise < .003%, 20 Hz to 20 kHz, unweighted
SMPTE IM < .005%
Channel phase match 0o
Transport delay < 2.3 mS
(All measurements made with 48 kHz sample rate, fixed audio delay, zero pitch shift)

Delay Pulse Input

BNC connector accepts a TTL pulse (active high) to control the offset delay for automatic lip sync correction.
Front Panel Indicators
Input level Dual LED bar graph
Status and modes 20 x 2 LCD display


AC Input 110-120/220-240 V, 50/60 Hz
Consumption ? W

Width 19.0" (48.3 cm)
Height 1.75" (4.5 cm)
Depth 18.5" (47 cm)
Weight ? lb (? kg)


Operating Temperature 0oC to 45oC
Storage Temperature -55oC to +75oC
Humidity 10% to 95%, non-condensing

Pat. 5,202,761, 4,313,135, RE 33,535 Pat. Pending

Pixel Instruments continuing product development programs may result in changes to specifications and features without notice.