Introduction | GSM | DECT | PCS1900 |
DECT Application Benchmarks
2. DECT Low side injection
igure 23. Application circuit, DECT low side injection
This was simulated under the following conditions:-
| VCC | 3 V |
|---|---|
| V CP, V VCO | 4.6 V |
| Comparator frequency | 1728 kHz |
| Prescaler divide ratio | 32/33 |
| Reference oscillator | 27.648 MHz, -3 dBm |
| RF out | 1776.384 MHz |
| Ambient temperature | 25°C |
| VCO | Murata MQE 520-1767 (Kv = 31 MHz/V) |
Parts list:
| C1 | 100 pF |
|---|---|
| C2 | 10 nF |
| C3 | 10 µF |
| C4 | 100 pF |
| C5 | 33 pF |
| C6 | 33 pF |
| C10 | 100 pF |
| C11 | 10 µf |
| R3 | 0 Ω |
| R4 | 51 Ω |
| R5 | 47 κΩ |
| R6 | 47 κΩ |
| R7 | 47 κΩ |
| R8 | 18 Ω |
| R9 | 18 Ω |
| R10 | 18 Ω |
Loop filter:
| C7 | 22 nF |
|---|---|
| C8 | 220 nF |
| C9 | 1.5 nF |
| R1 | 1.8 κΩ |
| R2 | 150 κΩ |
| Phase noise performance | Measured value | Unit | Remarks |
|---|---|---|---|
| @1776.384 MHz | -80.5 | dBc/Hz | maximum within loop bandwidth = 13 kHz |
| Phase error | RMS value | Peak value | Unit |
|---|---|---|---|
| @1776.384 MHz | 1.0 | 2.4 | degrees |
| Hopping time | Measured value | Unit | Remarks |
|---|---|---|---|
| 1769.472 MHz → 1785.024 MHz | 388 | µs | |
| 1785.024 MHz → 1769.472 MHz | 388 | µs |
- 1
- Close to measurable limit
Figure 24 - Spurious performance at 1776.384 MHz -70.0 dBc
Figure 25 - Phase noise performance; C/N= -80.5 dBc/Hz, maximum within loop bandwidth
Figure 26 - Phase noise performance @ Δ f= 1 MHz from carrier; C/N= -139.3 dBc/Hz ⇔ -146.3 dBm/Hz
Figure 27 - Phase noise performance @ Δ f= 10 MHz from carrier; C/N= -147.6 dBc/Hz « -154.6 dBm/Hz (close to measurable limit)
Figure 28 - Hopping time 388µs for frequency step 1769.472MHz → 1785.024MHz (Measurement triggered 100µs after PLL was programmed, therefore the marker readout shown on top is 100µs longer than the actual hopping time)
Figure 29 - Hopping time 427µs for frequency step 1785.024MHz → 1769.472MHz (Measurement triggered 100µs after PLL was programmed, therefore the marker readout shown on top is 100µs longer than the actual hopping time)
Figure 30 - Phase error @1776.384MHz, RMS value: 1.0°, peak value: 2.4°
