Wideband and narrowband receiver
View Patent ↗Systems and methods provide a receiver design capable of both wideband (high symbol rate) and narrowband (low symbol rate) operations requirements without compromising narrowband performance. Moreover, such a receiver design can be very low cost, and eschewing the need for any expensive and/or specialized elements. A receiver configured in accordance with various embodiments utilizes a fully integrated tuner in which narrowband filters are configured to be bypassable when in wideband (high symbol rate) mode in favor of fixed wideband filters. Additionally, an analog-to-digital converter (ADC) can be implemented with digital gain for wideband operation, as well as digital data bit mapping to accommodate industry standard application-specific integrated circuits (ASICs) interfaces, such as from a 12 bit ADC core to an 8 bit digital interface.
1. An apparatus, comprising:
a tuner comprising first and second narrowband filters for operating on a narrowband carrier signal, wherein the first and second narrowband filters are bypassable narrowband filters;
first and second wideband filters, separate from the first and second narrowband filters and connected in series with a respective one of the first and second narrowband filters, the first and second wideband filters for operating on a wideband carrier signal when the first and second narrowband filters are bypassed, wherein each of the first and second narrowband filters is bypassed when a signal passes through but is not filtered by the narrowband filter; and
an analog to digital converter (ADC) including first and second digital gain modules for adding digital gain to the wideband carrier signal.
2. The apparatus of claim 1 , wherein the tuner further comprises a variable gain amplifier for applying gain to a receiver input carrier signal, the receiver input carrier signal comprising one of the narrowband carrier signal or the wideband carrier signal.
3. The apparatus of claim 2 , wherein the tuner further comprises a zero-IF down-conversion portion for converting the receiver input carrier signal to baseband.
4. The apparatus of claim 1 , wherein the narrowband carrier signal has a symbol rate of less than 45 MSPS.
5. The apparatus of claim 1 , wherein the wideband carrier signal has a symbol rate of greater than or equal to 45 MSPS.
6. The apparatus of claim 1 , wherein the first and second wideband filters are fixed wideband filters.
7. The apparatus of claim 1 , wherein the first and second wideband filters are implemented external to the tuner.
8. The apparatus of claim 1 , wherein the first and second narrowband filters comprise variable bandwidth low-pass filters, and wherein one of the first and second narrowband filters filters an in-phase component of the narrowband carrier signal and another one of the first and second narrowband filters filters a quadrature-phase component of the narrowband carrier signal.
9. The apparatus of claim 1 , wherein the ADC comprises a dual channel ADC for receiving filtered and down-converted in-phase and quadrature-phase components of one of the narrowband and wideband carrier signal.
10. The apparatus of claim 9 , wherein the ADC further comprises first and second digital gain modules for adding the digital gain to the in-phase and quadrature-phase components of the wideband carrier signal.
11. The apparatus of claim 10 , wherein the ADC further comprises first and second 12-bit cores for digitizing the in-phase and quadrature-phase components of one of the narrowband and wideband carrier signal.
12. The apparatus of claim 11 , wherein the ADC further comprises first and second 8-bit mapping modules for mapping the in-phase and quadrature-phase components of one of the narrowband and wideband carrier signal from 12 bits to 8 bits in accordance with an 8-bit interface to a demodulation processor.
13. A method, comprising:
receiving an input carrier signal;
applying a first gain to the input carrier signal;
down-converting the input carrier signal;
filtering the down-converted input carrier signal utilizing one of a bypassable narrowband filter when the input carrier signal has a low symbol rate and a wideband filter, separate from the narrowband filter and connected in series with the bypassable narrowband filter, when the input carrier signal has a high symbol rate and the bypassable narrowband filter is bypassed, wherein the bypassable narrowband filter is bypassed when a signal passes through but is not filtered by the bypassable narrowband filter;
digitizing the input carrier signal;
adding digital gain to the input carrier signal if the input carrier signal has a high symbol rate; and
outputting the digitized input carrier signal.
14. The method of claim 13 , further comprising mapping the input carrier signal from 12-bit digital data to 8-bit digital data.
15. The method of claim 14 , wherein the mapping is performed at an analog to digital converter (ADC) comprising an 8-bit mapping module.
16. The method of claim 13 , wherein the receiving of the input carrier signal, the application of the first gain, the down-conversion, and the filtering utilizing the narrowband filter is performed at a receiver tuner chip.
17. The method of claim 16 , wherein the filtering utilizing the wideband filter is performed at an external filter.
18. The method of claim 15 , wherein the digitizing and the addition of digital gain is performed at the ADC.
19. A satellite set-top box, comprising:
a receiver tuner for:
receiving an input carrier signal, the input carrier signal comprising one of a narrowband carrier signal or a wideband carrier signal;
applying a first gain to the input carrier signal;
separating the input carrier signal into an in-phase component and a quadrature-phase component;
down-converting the in-phase and quadrature-phase components; and
filtering the down-converted in-phase and quadrature-phase components utilizing a bypassable narrowband filter when the input carrier signal is the narrowband carrier signal;
a wideband filter, separate from the bypassable narrowband filter and connected in series with the bypassable narrowband filter, for filtering the input carrier signal when the input carrier signal is the wideband carrier signal and the bypassable narrowband filter is bypassed, wherein the bypassable narrowband filter is bypassed when a signal passes through but is not filtered by the bypassable narrowband filter; and
a dual channel analog to digital converter (ADC) for:
digitizing the filtered and down-converted in-phase and quadrature-phase components;
adding digital gain if the input carrier signal is the wideband carrier signal; and
outputting the digitized input carrier signal.
20. The satellite set-top box of claim 19 , further comprising a demodulation processor for demodulating the in-phase and quadrature-phase components of the input carrier signal.
21. The satellite set-top box of claim 20 , wherein the demodulation processor and the dual channel ADC are operatively connected via an 8-bit interface, and wherein the dual channel ADC comprises two 12-bit ADC cores.
22. The satellite set-top box of claim 21 , wherein the dual channel ADC further comprises first and second 12-bit to 8-bit mapping modules for mapping the in-phase and quadrature-phase components of the input carrier signal to 8-bit digital data from 12-bit digital data.