7027 & 7027A Frequency Counter Modules
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Mô tả
The 7027 and 7027A are high quality 3GHz and 6GHz universal frequency counter modules that offer period measurement, frequency ratio, pulse width and event counting. Each module uses an advanced reciprocal frequency counting technique to achieve high resolution at all frequencies. A DC coupled input enables VLF measurements to be made (down to 1mHz).
The timebase uses a high quality TCXO crystal with a very low ageing rate. An external reference can also be used.
The large 10 digit LCD display has a full set of annunciators. Measurement times can be set between 0.3 seconds and 10 seconds.
Pulse width measurements can be made from rising to falling or falling to rising edge with adjustable thresholds. A variable attenuator is incorporated the input impedance is switchable between 1MΩ and 50Ω.
Full remote control and read-back is provided via a USB interface, situated at the rear of the calibration bench console.
High measurement accuracy
The 7027 and 7027A use a high quality temperature compensated internal frequency reference (TCXO) which has a low aging rate and is stable to within ±1ppm over the full temperature range. Its short warm-up time allows accurate measurements.
An External Reference input is provided and changeover from the internal timebase is automatic when an external reference standard is connected.
High resolution
For frequency, period and frequency ratio functions the modules use a reciprocal counting technique to provide high resolution at all frequencies. Eight significant digits of answer are produced in a 1 second measurement time, nine digits in 10s and ten digits in 100s with a granularity of less than 2 counts in the least significant digit.
Flexible signal conditioning
Input A has configurable coupling (AC or DC), input impedance (1MΩ or 50Ω), attenuation (1:1 or 5:1), threshold (fully variable) and active edge, and can be used for frequencies in the range 0.001Hz to >125MHz.
Input B is a nominal 50Ω input for frequencies in the range 80MHz to > 3GHz.
Input C (7027A only) uses a standard N connector and has a nominal 50Ω input for frequencies in the range 1.8GHz to > 6GHz.
Multiple measurement functions
The 7027 and 7027A can measure frequency, period, pulse width, duty cycle and frequency ratio, as well as event counting (totalise).
Remote control and read-back via USB
Both modules incporporate a USB interface which allows it to be remotely controlled using RS-232 protocol via a computer’s USB port. Connection is via the rear of the calibration bench.
Ten digit LCD
Both modules feature a high contrast display has ten 12.5mm (0.5”) high digits along with a comprehensive set of annunciators. These show input configuration and function, measurement time and status, external reference connection, low battery and the units of the measurement which may be Hz, kHz, MHz, ns, us, ms or s.
Thông số kỹ thuật
| Input A | Input Coupling: AC or DC Input Impedance: 1MΩ//25pF (DC or AC coupled), or 50Ω (AC coupled only) Attenuation: 1:1 or 5:1 Active Edge: Rising or falling, or width high or low Low Pass Filter: 50kHz cut-off, or None Frequency Range: 0.001Hz to > 125MHz (1MΩ, DC coupled). < 30Hz to > 125MHz (1MΩ, AC coupled). < 500kHz to > 125MHz (50Ω, AC coupled). Sensitivity: Sinewave – 15mVrms 30Hz to 100MHz, 25mV to 125MHz at optimum threshold adjustment. Signal Range: 1MΩ, DC – 0 to 3.3V (1:1) or 1 to 12V (5:1). 1MΩ, AC – up to 1Vrms (3Vpp) (1:1) or up to 4Vrms (12Vpp) (5:1). 50Ω, AC – up to 1V rms above 300kHz Trigger Threshold: DC coupled – 0 to 2V (1:1) or 0 to 10V (5:1). AC coupled – Average ± 200mV (1:1) or ± 1V (5:1). |
| Input B | Input Impedance: 50Ω (AC coupled) Frequency Range: <80MHz to >3000MHz Sensitivity: Sinewave – 12mVrms 80MHz-2GHz, 25mV to 2.5GHz, 50mVrms to 3GHz Signal Range: <0dBm recommended, +13dBm (1Vrms) maximum |
| Input C (7027A only) | Input Impedance: 50Ω (AC coupled)
Frequency Range: <1800MHz to >6000MHz
SensitivitySinewave: – 12mVrms 80MHz-2GHz, 25mV to 2.5GHz, 50mVrms to 3GHz
Signal Range: <0dBm recommended, +13dBm (1Vrms) maximum
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| External Reference | Input Impedance: >100kΩ, AC coupled Frequency: 10MHz Signal Level: TTL, 3Vpp to 5Vpp CMOS or 1 to 2Vrms sinewave |
| Maximum Input Voltage | Input A and Input B: 30Vdc; 30Vrms 50Hz/60Hz reducing to 1Vrms above 1MHz |
| Frequency | A Input Range: 0.001Hz (DC coupled) to >125MHz B Input Range: 80MHz to >3000MHz Resolution: up to 10 digits (see below) or 0.001Hz |
| Period | A Input Range: 8ns to 100s (DC coupled) B Input Range: 333ps to 12.5ns Resolution: up to 10 digits (see below) |
| Pulse Width Mode (Input A only) |
Functions: Width high, width low, ratio H:L (high time to low time) and duty cycle Pulse Width Range: 40ns to 1000s Averaging: Automatic within measurement time selected, up to 50 pulses Resolution: 20ns for one pulse; up to 1ns or 10 digits with multiple pulse averaging. 0.01% for Ratio H:L & Duty Cycle. |
| Total Count (Input A only) | Count Range: 1 to 9 999 999 999 Minimum Width: 8ns |
| Frequency Ratio B:A | Resolution: Equal to the resolution of the two frequency measurements. If the ratio exceeds 10 digits, 6 digits and the exponent are displayed. |
| Measurement Time | Selectable as 100s, 10s, 1s or 0.3s. The instrument displays the average value of the input signal over the measurement time selected, updated every 2s, 1s, 0.5s or 0.3s respectively. The hardware captures the count values and continues measuring without any dead time. |
| Resolution | The displayed resolution depends upon measurement time and input frequency. The basic resolution of period is 8 digits for every 2 seconds of measurement time. Frequency resolution is the reciprocal of period resolution. Usable resolution can be reduced by noise at low frequencies. |
| Accuracy | Measurement accuracy is timebase accuracy + measurement resolution + 2 counts. |
| Measurement Clock | 50MHz |
| Internal Reference | 10MHz TCXO with electronic calibration adjustment (> +/- 8ppm) |
| Temperature Stability | Better than ± 1ppm over rated temperature range |
| Initial Error | < ± 0.2ppm at 25°C |
| Ageing Rate | < ± 1ppm/year |
| Noise Filter | The Filter key controls a low pass filter, with a cut-off frequency of about 50kHz, to ensure more stable readings at low frequencies. |
| Hold | Pressing the Hold key will stop further measurements being made and the current measured value will remain in the display, with the Hold indicator on, until the Hold key is pressed again. A long press on the Hold key clears old data and restarts the measurement. |
| Intelligent Power Switching | The unit automatically selects the best available power source of AC adaptor, USB or battery. Intelligent switching avoids discharging the battery overnight when operated from externally switched AC power. A press-to-measure facility allows a quick measurement to be made by pressing a function select key which will power the instrument up in the corresponding function. The instrument will automatically switch off 15 seconds after the last key-press. |
| Signal Activity Indication | Dual bi-colour LEDs show signal activity & indicate whether a DC coupled signal is above or below trigger threshold. |
| Display | 10 digits |
| Interface | USB on rear of bench console |
| Module Width | 295mm (primary console fitting only) |
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