5721 Tri-Notch Filter
The Netcom 5721 tri-notch filter passes 225 MHz to 750 MHz and places three independently tunable notches inside that range. Notch 1 covers 486 to 573.9 MHz, notch 2 covers 574 to 661.9 MHz and notch 3 covers 662 to 750 MHz. Each notch is set in 100 kHz steps and each can be switched off on its own, so you use only the notches you need.
Rejection is 15 dB minimum at the notch centre, held across ±2 MHz. The notch keeps the same absolute bandwidth wherever it is tuned, rather than widening with frequency, so a notch at 700 MHz is no wider than one at 500 MHz.
Insertion loss depends on how many notches are switched in: 1.3 dB maximum with all three bypassed, 5.3 dB with one active, 6.2 dB with two and 7.0 dB with all three. Control is by SPI serial interface and each notch settles in under 50 microseconds. The filter runs from 3.3 VDC at 55 mA, handles +25 dBm, and is internally temperature compensated. It measures 1.70 x 1.80 x 0.35 inches and works from -40 to +85 °C.
- Specifications
| Passband Frequency Range | 225 to 750MHz |
| Notch 1 Center Frequency (NCF) Range | 486 – 573.9MHz |
| Notch 2 Center Frequency (NCF) Range | 574 – 661.9MHz |
| Notch 3 Center Frequency (NCF) Range | 662 – 750MHz |
| Notch Rejection at NCF±2MHz | 15dB min |
| Passband Insertion Loss (All Notches Off) | 1.3dB max |
| Insertion Loss at NCF±10MHz (1 Notch Active) | 5.3dB max |
| Insertion Loss at NCF±10MHz (2 Notches Active) * | 6.2dB max *** |
| Insertion Loss at NCF±10MHz (3 Notches Active) ** | 7.0dB max *** |
| Impedance (Input/Output) | 50 Ω |
| VSWR | 2.5:1 |
| Temperature Range | -40°C to +85°C |
| Notch Drift Over Temperature | Internally Compensated |
| RF Power Handling | +25dBm |
| IIP3 | TBD |
| DC Power | |
| DC Voltage | 3.3 VDC ±0.3 VDC |
| DC Current Max | 55mA |
| Control Interface | SPI Serial Input |
| Tuning Resolution | 100KHz |
| Switching Speed, 90% RF Power (typical) | < 50μsec |
| Dimensions [L x W x H] | 1.70 X 1.80 X 0.35 inches
43.20 X 45.20 X 8.90 mm |