Digital to QAM Transcoder
FEATURES
Front panel backlit display and buttons allow easy setup and monitoring of operating mode and parameters. High output, 61 dBmV, agile QAM modulator and upconverter are built in, operating up to 1024QAM. RS232 serial interface provides for remote control programming and monitoring. The field installable ASI input or second tuner/demodulator modules (if not factory installed) add the transport stream multiplexing function. Input tuner/demodulator(s) tune off-air or CATV channels between 54 and 860 MHz and provide demodulation of 8VSB, 16VSB, or QAM modes from 16QAM to 256QAM. ATSC, ITUA (DVB), or ITUB (DigiCipher® II) FEC modes are supported. A wide range equalizer suppresses multipath effects on ATSC signals. Off-air ATSC mode incorporates a NTSC co-channel rejection filter. Major channel number pass through or remarking to RF output channel is selectable. Operates in a fixed output clock mode and processes null packets when required to maintain the set fixed clock rate. Program filtering allows the user to select which MPEG programs present in the input streams are to be included in the output or discarded. PSIP options include several modes of operation. MPEG program numbers and minor channel numbers of input B or the ASI input may be offset to prevent duplication of the input A numbering. Rewriting of the MPEG tables is provided when two input streams are multiplexed. PCR restamping is performed when necessary. 61 dBmV QAM low phase noise output is agile on CATV or broadcast channels from 54 to 1002 MHz. High MER output signal quality. 1U tall package with internal power supply conserves rack space. Manufactured in the USA.
PRODUCT DESCRIPTION
The R. L. Drake model DQT1000 is a professional quality, digital headend transcoder product that tunes and demodulates MPEG2 or H.264 encoded VSB or QAM modulated signals from an off-air broadcast or CATV source or accepts an ASI input source. After error correction, it remodulates and upconverts the recovered MPEG2 transport stream onto a new QAM modulated digital output channel. The standard DQT1000 is supplied with two tuner/demodulators. The DQT1000 may also be special ordered with a single tuner/demodulator. For these units, a second tuner/demodulator module is also available by special order. An optional ASI input module is also available as a field installable option. If a DQT1000 is configured with two tuner/demodulators and an ASI input module, only Tuner/Demod A and one of the other inputs may be used and multiplexed at one time. These options may be added to the standard DQT1000, all within the DQT1000 chassis. The output section of the DQT1000 consists of a QAM modulator with an agile RF upconverter with an output of up to 61 dBmV that tunes from 54 to 1002 MHz. With one tuner/demodulator the DQT1000 functions as a digital channel processor. One can receive an ATSC, DVB, or DigiCipher® II input signal on any channel in the CATV or broadcast spectrums in 8VSB, 16VSB, or 16QAM to 256QAM modulation and remodulate as a DVB or DigiCipher® II QAM signal. While performing this process, the DQT1000 will apply the appropriate Forward Error Correction (FEC) to the received input stream, drop and add null packets as required by the selected output bit rate, perform PCR correction and re-encode with the appropriate output FEC for the modulation chosen. The QAM output signal is then up-converted to a new RF output channel using Drake's high performance low noise circuitry. When the second tuner/demodulator is installed, the DQT1000 can multiplex the demodulated transport streams from two separate VSB or QAM modulated RF inputs and modulate all of the data onto a single RF output channel at 256QAM modulation. This allows a cable operator to distribute two local ATSC broadcast channels in one 6 MHz wide cable channel without losing any of the original programs and without any additional compression of the broadcast signal. The DQT1000 provides a program filter function (a new Select Program menu) and offers superior upconverter specifications with phase noise reduced to a level that is compatible with QAM modes up though 1024QAM. Also, the DQT1000 can be controlled with the Drake Digital Headend Remote Control Software, version 2.4 or later, for remote programming of operating parameters or remote monitoring of operations. The ASI input module accessory is also available. When this module is added, one of the inputs may be delivered to the DQT1000 via this MPEG2 transport stream compable ASI input. As an example, this option may be used to input from a direct feed sent from a local broadcast station via fiber or from a compatible satellite receiver transport stream output.
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