Overview
The Lectrosonics SRc Dual Channel Slot-Mount Receiver - Block A1 (470.100 - 537.575 MHz) features two separate receivers built into a single, ultra compact housing with adapters for video camera receiver slots and for standalone use. Digital Hybrid Wireless technology provides superb, compandor-free audio quality and compatibility with other wireless systems. The RF performance is extremely stable over a very wide temperature range, making the receiver perfectly suited to the rough environmental conditions found in field production. DSP compatibility modes allow the receiver to be used with a variety of Lectrosonics systems, other brands of wireless systems and with Lectrosonics IFB transmitters.
Digital Hybrid Wireless
Digital Hybrid Wireless combines digital audio with an analog FM radio link to provide both outstanding audio quality and noise-free RF performance. Using a patented algorithm to encode 24-bit digital audio information in the transmitter into an analog format, the encoded signal is then transmitted over an analog FM wireless link. At the receiver, the signal is then decoded to restore the original digital audio. This process eliminates compandor artifacts and produces an audio frequency response flat to 20 kHz.
Front Control Panel
The front panel features a menu-driven LCD interface and (4) membrane switches, that are used to view and alter settings. The main LCD window displays the pilot tone indicator, diversity activity, RF level, audio level, and transmitter battery status for both receivers. To find clear operating frequencies, a built-in spectrum analyzer scans across the tuning range of the receiver and displays a histogram of RF activity within the tuning range. Areas of little or no RF activity are easily recognizable.
Controls & Indicators include:
- Sealed panel with membrane switches
- LCD monitors pilot tone
- Antenna phase
- Receiver battery level
- Transmitter battery status
- Audio level
- RF level
The (2) internal receivers can be operated separately, each using switching, antenna combining diversity, or in tandem with ratio diversity reception. The audio outputs of the receivers can be mixed internally, or left separated for discrete recording tracks or external mixing.
A variety of output adapters and mounting options are available for camera slot operation. The receivers are powered from an external 7-18V DC source.
Three Block Tuning Range
Each SRc receiver tunes across a range of over 76 MHz, covering three standard Lectrosonics frequency blocks. SRc-A1 uses the A1 Band, covering Block 470, 19, and 20 (470.100 to 537.575 MHz).
RF Front-End with Tracking Filter
A wide tuning range is helpful in finding clear frequencies for operation, however, it also allows a greater range of interfering frequencies to enter the receiver. The UHF frequency band, where almost all wireless microphone systems operate, is heavily populated by high power TV transmissions. The TV signals are immensely more powerful than a wireless microphone transmitter signal and will enter the receiver even when they are on significantly different frequencies than the wireless system.
This powerful energy appears as noise to the receiver, and has the same effect as the noise that occurs with extreme operating range of the wireless system (noise bursts and dropouts). To alleviate this interference, front-end filters are needed in the receiver to suppress RF energy below and above the operating frequency. Each receiver employs a variable frequency, tracking filter in the front-end section (the first circuit stage following the antenna). As the operating frequency is changed, the filters re-tune to stay centered over the selected carrier frequency.
In the front-end circuitry, a tuned tracking filter is followed by an amplifier and then another tuned tracking filter to provide the selectivity needed to suppress interference, yet provide a wide tuning range and retain the sensitivity needed for extended operating range.
IF (Intermediate Frequency) Filters
Following the front-end, the incoming RF signal in each receiver is mixed down to a lower frequency for additional filtering with two SAW (surface acoustic wave) filters. The use of two filters significantly increases the depth of filtering while preserving sharp skirts, constant group delay, and wide bandwidth.
Digital Pulse Counting Detector
The SRc Series receivers use an elegantly simple, yet highly effective digital pulse counting detector to demodulate the FM signal rather than a conventional quadrature detector. This eliminates thermal drift, improves AM rejection, and provides very low audio distortion.
DSP-Based Pilot Tone
The Digital Hybrid system design uses a DSP-generated ultrasonic pilot tone to reliably mute the audio when no RF carrier is present. The pilot tone must be present in conjunction with a usable RF signal before the audio output will be enabled. 256 pilot tone frequencies are used across each 25.6 MHz block within the tuning range of the system. This alleviates erroneous squelch activity in multichannel systems where a pilot tone signal can appear in the wrong receiver via IM (intermodulation).
Auto Power State Restoration
The receiver's firmware remembers whether it was turned on or off when power is disconnected and returns to that state when power is restored.
SmartSquelch
This DSP-based algorithm optimizes the receiver performance in very weak signal conditions. The RF level and supersonic noise in the audio are continuously monitored to determine the appropriate noise reduction needed and the point at which squelch (complete muting of the audio) is necessary.
SmartTune Frequency Selection
SmartTune simplifies setup by scanning the tuning range of the receiver or a selected frequency block, and automatically setting a channel to the best available frequency. A prompt appears, reminding the user to use IR sync or manual settings to tune the transmitter to the selected frequency, then turn it on so the receiver sees it. Then, a prompt asks if the process should continue for the second channel. This process allows very quick and accurate tuning, whatever the RF environment.
Optional Rear Panel and Slot Adapter Kits
Several different rear panel adapters are available (sold separately) to configure the receiver for popular camera slots and for stand-alone use. The rear panels are held in place by two screws and are easily changed. Camera slot adapter kits include top panel bezels with hardware for a secure fit into the camera body.
The receiver can also be powered with an optional battery "sled" adapter (not included) that accepts your standard "L" and "M" style rechargeable batteries. The adapter includes an integrated SREXT plate for the rear panel audio outputs. Typical runtime with a 7.2V, 2200 mA "L" style battery is approximately 11 hours. Please contact an AbelCine salesperson for details & availability.
Specifications:
- Operating Frequency: Band A1 (470.100 - 537.575 MHz)
- Frequency Selection Steps: Selectable; 100 kHz or 25 kHz
- Receiver Type: Dual conversion, superheterodyne
- IF Frequencies:
- 1: 248.450 MHz and 350.000 kHz
- 2: 243.950 MHz and 250.000 kHz
- Frequency Stability: ±0.001 %
- Front End Bandwidth: 20 MHz @ -3 dB
- Sensitivity:
- 20 dB SINAD: 1.0 uV (-107 dBm), A weighted
- 60 dB Quieting: 2.2 uV (-100 dBm), A weighted
- Squelch Quieting: Greater than 100 dB typical
- AM Rejection: Greater than 60 dB, 4 uV to 1 Volt
- Modulation Acceptance: 85 kHz
- Image & Spurious Rejection: 85 dB
- Third Order Intercept: 0 dBm
- Diversity Method: SmartDiversityTM phased antenna combining or Ratio Diversity using both receivers for a single audio channel
- FM Detector: Digital Pulse Counting Detector operating at 250 and 350 kHz
- RF Spectrum Analyzer: Coarse and fine scanning modes for RF spectrum site survey
- Antenna Inputs: 50 Ohm; SMA female connectors
- Audio Output Connectors:
- Interchangeable D connector adapters for camera slot interfaces
- Dual TA3 male (mini XLR) balanced output adapter
- Balanced output adapter with fixed cables
- Front panel audio output (5P model): Control panel TA5M with two balanced outputs
- Audio Output Level: Adjustable -50 to +5 dBu in 1 dB steps; unbalanced output is 6 dB lower
- Audio Channel Crosstalk: -80 dB or better
- Front Panel Controls & Indicators:
- Sealed panel with membrane switches
- LCD monitors pilot tone, antenna phase, receiver battery level, transmitter battery status, audio level, RF level
- Audio Test Tone: 1 kHz, -50 dBu to +5 dBu output (bal); 1% THD
- Transmitter Battery Type Selection: 9V alkaline, 9V lithium, AA alkaline, AA lithium, NiMH
- Phase Invert: Audio output phase normal or inverted
- Compatibility Modes:
- NA HYBR: North American Digital Hybrid Wireless
- NU HYBR: ETSI Compliant Nu Digital Hybrid Wireless
- MODE 3: Other manufacturer*
- 200 SER: 200 Series transmitters
- 100 SER: 100 Series transmitters
- MODE E: Other manufacturer*
- EU HYBR: European Digital Hybrid Wireless®
- 300 SER: 300 Series transmitters (European)
- MODE 7: Other manufacturer*
- MODE 6: Other manufacturer*
- IFB SER: Standard IFB mode
- *Contact the factory for details on other manufacturers
- SmartNR (Noise Reduction): OFF, NORMAL, FULL modes (available in Digital Hybrid mode only)
- Audio Performance (Overall System):
- Frequency Response: 32 Hz to 20 kHz (+/- 1dB)
- THD: 0.15% (system) typical in Digital Hybrid mode
- System Dynamic Range:
- Smart NR: OFF, NORMAL, FULL
- No Limiting: 103.5, 107.0, 108.5
- With Limiting: 108.0, 111.5, 113.0
- NOTE: The dual envelope "soft" limiter provides exceptionally good handling of transients using variable attack and release time constants; once activated, the limiter compresses 30+ dB of transmitter input range into 4.5 dB of receiver output range, thus reducing the measured figure for dynamic range with no limiting by 4.5 dB
- Rear Panel Controls & Features:
- Audio output connectors
- External DC input
- Powering & Current Consumption:
- 7V to max. 18V DC; 2.6W
- 145 mA at 18V DC
- 290 mA at 7V DC
- Runtime with SRBATTSLED Adapter: 7.2V, 2200 mAH "L" style battery will typically provide over 7 hours of operation
- Transmitter Battery Level Tracking: LCD display with battery icon or timer readout
- Operating Temperature: -4°F to +122°F (-20°C to +50°C)
- Weight: 0.49 lb (225 g) with SREXT adapter
- Overall Dimensions (with SREXT adapter): 2.92" x 4.93" x 1.22" (74mm x 125mm x 31mm)
What's in the Box
- Lectrosonics SRc Dual Channel Slot-Mount Receiver - Block A1 (470.100 - 537.575 MHz)
Specifications
Key Highlights
- Dual Channel Slot-Mount RX
- Block 470, 19, and 20
- 470.100 to 537.575 MHz
