1Overview
The Model 875 is a vector-modulated signal generator covering 10 MHz to 40 GHz continuously. It supports ultra-fast switching down to 200 ns and enables rapid CW sweeps, chirping, intra-pulse modulation, pulse shaping, and low phase noise operation in a single instrument.
At its core is an internal I/Q modulator that produces custom and standards-based waveforms at ultra-high I/Q data rates from deep waveform memory. Real-time Pulse Descriptor Word playback lets the 875 emulate complex radar and electronic warfare environments, and multiple units run phase-coherent across up to four channels. Frequency coverage is selectable by model, from 4 GHz through the full 40 GHz span.
2Key Features
- Internal I/Q modulator for custom and standards-based vector waveforms.
- Ultra-fast switching and modulation down to 200 ns.
- Deep memory and wideband support at ultra-high I/Q data rates.
- PDW playback with real-time input over the Fast Control Port.
- Multi-channel synchronization, phase-coherent across up to four channels.
- Excellent phase noise and wideband linear chirp.
- Digital modulation schemes: ASK, FSK, MSK, PSK, plus GSM/EDGE, 3GPP FDD, HSDPA, GPS, and CDMA2000.
3Frequency & Output Power
The 875 covers 10 MHz to 40 GHz with 0.001 Hz resolution. Five frequency-range models let you buy only the coverage a program needs. Output power spans −50 to +20 dBm, extendable down to −90 dBm with a step attenuator option.
| Model | Frequency Range |
|---|---|
| 875-4 | 10 MHz to 4 GHz |
| 875-6 | 10 MHz to 6 GHz |
| 875-12 | 10 MHz to 12 GHz |
| 875-20 | 10 MHz to 20 GHz |
| 875-40 | 10 MHz to 40 GHz |
| Parameter | Specification |
|---|---|
| Frequency resolution | 0.001 Hz |
| Output power | −50 to +20 dBm (−90 dBm optional) |
4Phase Noise & Spectral Purity
The 875 pairs vector modulation with low phase noise. At a 1 GHz carrier it reaches −130 dBc/Hz at a 1 kHz offset, falling to −150 dBc/Hz at 100 kHz. Option LN improves the 10 Hz close-in figure from −87 to −100 dBc/Hz.
| Offset (1 GHz) | Phase Noise |
|---|---|
| 10 Hz | −87 dBc/Hz (−100 dBc/Hz with option LN) |
| 1 kHz | −130 dBc/Hz |
| 20 kHz | −145 dBc/Hz |
| 100 kHz | −150 dBc/Hz |
5Vector / I-Q & Pulse Descriptor Word
The 875 is built around vector modulation. An internal I/Q modulator generates custom and standards-based waveforms at ultra-high I/Q data rates from deep waveform memory, which supports arbitrary I/Q waveform playback, wideband linear chirp, and intra-pulse modulation. Standards-based digital schemes include ASK, FSK, MSK, and PSK, along with GSM/EDGE, 3GPP FDD, HSDPA, GPS, and CDMA2000. Option AIQ adds external analog I/Q inputs for driving the modulator from an external source.
For radar and electronic warfare emulation, the 875 plays back Pulse Descriptor Words. Each PDW specifies pulse width, amplitude, frequency, angle, and time of arrival, and PDWs upload over Ethernet or USB. With the Fast Control Port option, PDWs stream in real time, so the instrument can render dense, agile pulse trains on the fly. Phase-coherent operation across up to four channels supports MIMO and phased-array test.
| Capability | Specification |
|---|---|
| Vector modulation | Internal I/Q modulator, ultra-high I/Q data rates |
| Waveform memory | Deep memory for custom and standards-based waveforms |
| Digital schemes | ASK, FSK, MSK, PSK; GSM/EDGE, 3GPP FDD, HSDPA, GPS, CDMA2000 |
| PDW parameters | Pulse width, amplitude, frequency, angle, time of arrival |
| PDW upload | Ethernet or USB; real-time via Fast Control Port (option FCP) |
| External I/Q | Analog I/Q inputs with option AIQ |
6Frequency Switching & Sweep
CW switching is under 500 µs, dropping below 2 µs with option UFS. In vector and modulation modes the 875 switches in 200 ns, fast enough for intra-pulse agility. Complex list sweeps sequence frequency, power, and modulation states for automated test.
| Parameter | Specification |
|---|---|
| Switching speed (CW) | <500 µs (<2 µs with option UFS) |
| Switching speed (vector/modulation) | 200 ns |
| Sweeps | Complex lists |
7Specifications
| Parameter | Specification |
|---|---|
| Channels | 1 (desktop); 2, 3, or 4 (2U rackmount) |
| Frequency range | 10 MHz to 40 GHz (model dependent) |
| Frequency resolution | 0.001 Hz |
| Output power | −50 to +20 dBm (−90 dBm optional) |
| Switching speed | <500 µs (<2 µs with option UFS); 200 ns (vector/modulation) |
| Phase noise @ 1 GHz, 10 Hz | −87 dBc/Hz (−100 dBc/Hz with option LN) |
| Phase noise @ 1 GHz, 1 kHz | −130 dBc/Hz |
| Phase noise @ 1 GHz, 20 kHz | −145 dBc/Hz |
| Phase noise @ 1 GHz, 100 kHz | −150 dBc/Hz |
| Modulation | I/Q (vector); pulse; analog (AM, FM, PM); internal digital schemes; avionics (DME, VOR, ILS) |
| Sweeps | Complex lists |
| Remote control | Ethernet, USB; optional GPIB; SCPI v1999 |
| Reference input | 10 MHz, or variable 5 MHz to 250 MHz (option VREF) |
| Reference output | 10 MHz / 100 MHz |
| Benchtop dimensions (W × L × H) | 6.77″ × 11.412″ × 4.12″ [172 × 290 × 105 mm] |
| Benchtop weight | 6.0 lbs (8.0 lbs shipping) |
| Rackmount dimensions (2U) | 17.5″ × 24″ × 3.5″ [444 × 610 × 88 mm] |
| Rackmount weight | 40.0 lbs (42.0 lbs shipping) |
| Power supply | Not specified (verify) |
8Interfaces & Form Factor
The 875 controls over Ethernet and USB, with optional GPIB, using SCPI v1999. A 10 MHz reference input is standard, with a variable 5 MHz to 250 MHz input available through option VREF, and reference output at 10 MHz or 100 MHz. The Fast Control Port streams real-time PDWs for live EW scenarios.
A single-channel unit ships in a desktop chassis measuring 6.77″ × 11.412″ × 4.12″ at about 6.0 lbs. Two, three, and four-channel configurations ship in a 2U rackmount measuring 17.5″ × 24″ × 3.5″ at about 40.0 lbs, with phase-coherent operation across channels.
9Options & Configurations
Channel configurations: one channel in a desktop chassis, or two, three, or four channels in a 2U rackmount.
| Option | Description |
|---|---|
| -LN | Enhanced close-in phase noise |
| -LN+ | Enhanced close-in phase noise and long-term stability |
| -100k | Frequency extension down to 100 kHz |
| -AWGN | Additive white Gaussian noise |
| -UFS | Ultra-fast switching |
| -FCP | Fast Control Port (real-time PDW input) |
| -PHS | Phase-coherent switching (per output) |
| -MOD | Analog modulation |
| -IVM | Internal digital modulation schemes |
| -PE / -PE2 / -PE4 | Step attenuators (down to −90 dBm, −120 dBm; electrical) |
| -AVIO | Avionics modulation (DME, VOR, ILS) |
| -PDW | Pulse Descriptor Word |
| -SYNC | Multi-device synchronization |
| -VREF | Variable external reference input |
| -AIQ | External analog I/Q inputs |
| -SD | MicroSD card slot |
| -RM | 19″ 2U rackmount chassis |
| -GPIB | GPIB interface |
| -EB | External battery bank [P/N 7146] |
| P/N 7091 | 19″ 3U single/dual rackmount kit |
| P/N 7143 | Spare power supply |
10Applications
- Arbitrary I/Q waveform generation
- Radar signal simulation (PDW / EW)
- Receiver testing
- Avionics modulation emulation
- Pulse Descriptor Word agility
- Mobile radio chip (multi-standard) testing
- IEEE 802.11 a/b/g test and R&D
- MIMO (multiple input, multiple output)
11Ordering
Select a frequency-range model (875-4 through 875-40) and channel count (one desktop channel, or two to four in a 2U rackmount). Add PDW and FCP for real-time pulse descriptor playback, AIQ for external I/Q drive, LN or LN+ for phase noise, UFS for fast switching, and AVIO for avionics modulation. For configuration help, pricing, or a quotation, contact Berkeley Nucleonics at info@berkeleynucleonics.com or 800-234-7858.