- Quad-synchronized A/V clocks produce PLLs
- PLL1: 27 or 13.5 MHz
- PLL2: 148.5 or 74.25 MHz
- PLL3: 148.5/1.001 or 74.25/1.001 MHz
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PLL4: 98.304 MHz/2 X (X = 0 to 15)
- 3 × 2 video clock intersection
- Flexible PLL bandwidth optimizes jitter performance and lock-in times
- Soft resync to the new reference
- Digital deferral or free operation reference loss
- Lost reference and PLL lost lock status flags
- 3.3V single-power operation
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I 2 C Interface and Address Selection Pin (3 Countries)
illustrate
LMH1983 chip is a highly integrated, programmable audio/video (A/V) clock generator for broadcasting and professional applications. It can replace multiple PLLs and supports pressure control used in applications compliant with SMPTE Serial Digital Video (SDI) and Digital Audio AES3/EBU standards. It provides a low-jitter reference clock for any SDI transmitter without the need for additional clock cleaning circuits to meet strict output jitter specifications.
LMH1983 chip's functions include automatic input format detection, multiple A/V output formats, synchronous phase-locked or digital free operation modes, covering various automatic functions with programmable and simple programming. Recognized input formats include HVF synchronization for major video standards, 27MHz, 10MHz, 32/44.1/48/96 kHz audio word clocks.
A dual-level PLL architecture integrates four phase-locked loops for three on-chip VCOs. Phase One (PLL1) uses an external, low-noise, narrow loop with a 27 MHz bandwidth voltage-controlled crystal oscillator to provide a clean reference clock for the next stage. The second phase (PLL2, 3, 4) consists of three parallel main digital A/V clock base rates, including 148.5 MHz, 148.5/1.001 MHz, and 98.304 MHz (4 x 24.576 MHz) of the VCO's PLL simultaneously. The top of the clock and timing pulse indicator frame (TOF) generated by each PLL is produced.
When the reference is locked, the internal 10-bit ADC will track the loop filter control voltage. When the loss of reference (LOR) occurs, the LMH1983 chip can be programmed to hold down the control voltage and maintain the output accuracy of the prereference (typical value) at ± 0.5 ppm. LMH1983 chip can be configured to resynchronize deburring operations with previous references.
LMH1983 chip offers a space-saving LLP package with 6mm x 6mm 40 pins.
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- Three-speed (3G/HD/SD) SDI deserializer
- FPGA reference clock generation/cleaning
- Audio embedding/unembedding
- camera
- Frame Synchronization (Synchronous Phase-Locking, DARS)
- AD/DA conversion, editing, processing cards
- Keyers and flag inserters
- Format/Standard Converter
- Video monitors and projectors
- A/V testing and measurement equipment
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